I have a site that reviews personal medical devices. Each year, these medical devices get replaced a few times by their newer/improved versions, so the old devices are not available anywhere commercially, and it doesn't make sense to let people navigate to those product pages on my site. However, many of those products are great long tail keywords which rank well and bring substantial traffic.   My question is, what should I do with these product pages? My idea was to just make sure that they can't be navigated to from anywhere on my site, yet keep the links active, and put a "discontinued" notice on the product page, and recommend newer products. I'm wondering if this will hurt SEO though, to have links which cannot be found on the site be visitors? Should I take those links out of the sitemap, leave them in? Redirect the links to their newer product pages? Anyone dealt with this before?
I know this question is someway similar to  where they recommend using 404, but after reading  where they suggest to use 301 when changing site URLs (in the specific case was due to redesign/re factoring) I get a bit of confused and I hope someone could clarify for this specific example:   Let's say I have an eCommerce site, let's also say the final user inserted some interesting items in the site and the eCommerce webapp created the item pages at the URLs: http://...?id=20, http://...?id=30 etc. Now let's say some of these interesting items got many external links toward them from many other sites because some people found those items very interesting and linked to them. After some years the final user deletes those items, so obviously the pages and URLs http://...?id=20, http://...?id=30, etc. now do not exist anymore, but still many pages on the web are linking toward them.   What should the eCommerce site do now, just show a 404 page for those items?  But, I'm confused, wouldn't this lose all the Google PR passed by the external links to the items pages? So isn't it better to use 301 redirect to HOME PAGE that at least passes the PR to the HOME PAGE?    EDIT:  Well, according to answers the best thing to do so far is to do a 404/410.  In order to make this question more complete, I would like to talk about a special case, just to make sure I understood. properly.  Let's say the user creates those items again (the ones he previously deleted at point 4), maybe he changes a bit their names and description, but they are basically the same items. The webapp has no way to know these new added items were the old items so it obviously create them as new items with new URLs http://...?id=100, http://...?id=101, does it makes sense at this point to redirect 301 the old urls to the new ones?    ANOTHER EDIT (It would be VERY IMPORTANT TO UNDERSTAND):  Well according to the clever answers received so far it seems for the special case, explained in my last EDIT, I could use 301, since it's something of not deceptive cause basically the new pages is a replacement for the old page in term of contents. This is basically done to keep the PR passed from external link and also for better user experience.  But beside the user experience, that is debatable (*1), in order to preserve PR from external broken links why not just always use 301, In my understanding Google dislikes duplicated contents, but are we sure that 301 redirect to HOME PAGE is seen as duplicated contents for Google?!   Google itself  so if they consider 301 as duplicated contents wouldn't that be considered duplicated contents too? Why do they suggest it?  Let me provoke you: “why not just add a 301 to HOME PAGE for every not found page?”   (*1) as a user, when I follow a broken URL from some external link to some website's page I would stick more on this website if I get redirected to HOME PAGE rather than seeing a 404 page where I would think the website does not even exist anymore and maybe I don't even try to go to HOME PAGE of the website.
How to update kernel to the latest mainline version without any Distro-upgrade? Currently I'm running Linux-3.0 and I want to update it to Linux-3.3.1 the latest stable kernel release as mentioned at . Can I update to 3.3.1 in Ubuntu without any risk of crashes? I'm updating my kernel regularly as provided by the Update Manager..Currently I have Linux-3.0.0.17..Can I update?  NOTE:  The latest kernel version any user is supposed to use in Ubuntu is updated automatically via the Update Manager, so no action is normally required by user regarding kernel upgrades. What the question author is referring to is mainline kernel, see: I am rendering my scene with only one sample but all the renders of the same picture have a different seed value. How can I combine them correctly? I wrote a java-program that loads all the images and takes the average pixel color for each pixel of the images. Is that a correct way of combining the images? It doesn't reduce the noise very much so I am not happy with it. What can I do? How can I check if a directory exists in a Bash shell script? What command can be used to check if a directory exists or not, within a Bash shell script? How do I programmatically force an onchange event on an input? How do I programmatically force an onchange event on an input?  I've tried something like this:  var code = ele.getAttribute('onchange'); eval(code);   But my end goal is to fire any listener functions, and that doesn't seem to work.  Neither does just updating the 'value' attribute. Baby Rudin claim: $1+\frac{1}{3}-\frac{1}{2}+\frac{1}{5}+\frac{1}{7}-\frac{1}{4}+\frac{1}{9}+\frac{1}{11}-\frac{1}{6}...$ converges This sequence is a rearrangement of the series $1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+\frac{1}{5}...$. Note that at this point in the text we do not have any theorem about the convergence of rearrangements.  Let $\{s_n\}$ be the sequence of partials sums of the series then for $n \ge 0$  $s_{3(n+1)} = \sum ^n _ {k=0} \frac{1}{4k+1} + \frac{1}{4k+3} - \frac{2}{4k+4}$  We can view it as the sequence(on $n$) of partials sums of  $\sum_0 a_n = \sum_0 \frac{1}{4n+1} + \frac{1}{4n+3} - \frac{2}{4n+4}$  Where $|a_n| = a_n = \frac{1}{4n+4}\{\frac{3}{4n+1}+\frac{1}{4n+3}\} \le \frac{1}{4n^2}$.  By the comparison test $s_{3(n+1)}$ converges to some real $\alpha$.  But $s_{3(n+1)+1} = s_{3(n+1)}+ \frac{1}{4n+5}$ and $s_{3(n+1)+2} = s_{3(n+1)}+ \frac{1}{4n+5}+\frac{1}{4n+7} $hence we have a partition of $\{s_n\}$ into subsequences which tend to $\alpha$ and this implies $s_n \rightarrow \alpha$.  Is my proof correct? Any alternative solutions are appreciated. How "submitted", "to appear", "accepted" papers are evaluated in a CV? Assume a search committee is reading my CV and in the publication section they notice some of my papers are only submitted or claimed to appear in a journal (or accepted for publication in a journal). Sometimes the journal which has accepted the paper for publication lists the title of accepted articles before actually publishing them, but in the rest of cases there is no evidence to prove that the referee process of the paper is over and the journal has accepted the paper for publication. Also assume preprints of my papers are available in ArXiv. So, my questions are:   How a search committee interprets and evaluates those papers which are just submitted or are claimed to appear?  Does a search committee consider these types of publications less valuable than the published ones (assuming the same quality)?  Does a search committee refer to my preprints in ArXiv to evaluate my submitted or accepted papers? Is there an issue tracker for already reported Mathematica bugs? Creating rounded corners using CSS How can I create rounded corners using CSS? Misleading chat usercard on SE 2.0 chat Does the Great Old One warlock's telepathy from the Awakened Mind feature take an action? Does the Great Old One warlock's telepathy from the Awakened Mind feature take an action?  It doesn't seem too clear to our group and we have basically ruled it as equivalent to talking. Prove the following in $S_n$:  Let $\alpha = (a_1,a_2,\ldots,a_s)$ be a cycle and let $\pi$ be a permutation in $S_n$. Then $\pi\alpha\pi^{-1}$ is the cycle $(\pi(a_1),\ldots,\pi(a_s)).$     I'm not sure where to even start. Group of positive rationals under multiplication not isomorphic to group of rationals Anti-Matter Black Holes Assuming for a second that there were a pocket of anti matter somewhere sufficiently large to form all the type of object we can see forming from normal matter - then one of these objects would be a black hole.  Question is, would there be a difference between an anti matter black hole and a normal matter black hole - in terms of how would the matter/anti-matter make the black hole different, or would they be the same?  I would expect the answer to be that the black hole formed from anti matter would retain the anti-matter properties in such a way that if it was to merge with a black hole at same size formed from normal matter that they would annihilate  each other con convert into pure energy - Would that be a correct understanding? Simple & easy way to jail users I need a simple and easy way to jail users in their home directories in Oneiric. Do you have a simple configuration for jailing users, with full help, or some good web links?  I would be offering an online free public server with 10 to 20 GB free space. I don't know how many users. I want to give them SSH and SFTP so that they can connect through FileZilla. How can I make a macOS Mojave bootable USB installer in Windows 10? I have downloaded and saved macOS Mojave installation file from the Mac App Store into my external hard drive. Unfortunately, macOS has crashed on my Mac and now I need to install it again. I have used a software named TransMac to make a installation USB in windows following the steps in the link below:    But the provided USB drive after all these steps doesn't show up in my MacBook pro. Considering that I have saved Install macOS Mojave.app on my external hard drive, and I don't have access to any other Mac computers, How can I fix this issue and build a USB for installing Mojave? Example of a finitely generated module with submodules that are not finitely generated PHP: how do I copy a temp file upload to multiple places? If $\gcd(a,b)=1$, then $\gcd(a+b,a^2 -ab+b^2)=1$ or $3$. Hint:  $a^2 -ab +b^2 = (a+b)^2 -3ab.$  I know we can say that there exists an $x,y$ such that $ax + by = 1$.  So in this case, $(a+b)x + ((a+b)^2 -3ab)y =1.$  I thought setting $x = (a+b)$ and $y = -1$ would help but that gives me $3ab =1.$  Any suggestions? Flip x and y axes in Excel graph This should not be very difficult, but I cannot figure out how to do it.  I have a table similar to this     %low %high  0   0   12  1  13   26  ... 19  90   94 20  95  100   When I graph it, excel defaults to having the first column on the x axis and plotting the second and third column as y values. I want the first column to be on the y axis instead. I assume there is an easy way to do this, but I cannot figure it out. Most of the things I have found from searching have suggested the "Switch Row/Column" button, but that does something else.  Thanks for the help. I have a large set of pictures, and I want to apply predefined settings to each using the optional argument of the \includegraphics macro from the graphicx package.  I would like to define the settings once at the top of the file (like \def\settings{width=\textwidth, angle=90}), and then apply them to all of my images so that I can modify all of the settings from one place.  If I run the following code block, it gives me the versions of the error "Package xkeyval Error: 'width=\textwidth, angle=90' undefined in families 'Gin'", which seems to be because it's interpreting my entire group of settings as a single key input.  \documentclass{article} \usepackage{graphix} \begin{document}      \def\settingsA{width=\textwidth, angle=90}     \def\settingsB{page=1, scale=.1}     \def\settingsC{angle=90, scale=.5}      \begin{figure}         \includegraphics[\settingsA]{filename1.png}         \label{fig:oneofonehundred}     \end{figure}      \begin{figure}         \includegraphics[\settingsB]{filename2.pdf}         \label{fig:twoofonehundred}     \end{figure}      \begin{figure}         \includegraphics[\settingsC]{filename3.jpg}         \label{fig:threeofonehundred}     \end{figure}   \end{document}   What is the technique to modify this settings string so that it is interpreted correctly? How do I pass an optional argument that is interpreted as a set of arguments instead of one string?  Thanks in advance!