The most popular links posted by developers to Stack Overflow
The top python link, which should direct to <a href="http://www.crummy.com/software/BeautifulSoup/" rel="nofollow">http://www.crummy.com/software/BeautifulSoup/</a> instead directs to <a href="http://www.crummy.com/software/beautifulsoup/" rel="nofollow">http://www.crummy.com/software/beautifulsoup/</a> --which causes crummy.com to throw a 404 error at you.