1) Friendster had scaling issues. They insisted on keeping the x-degree-of-friendship-calculation which is quite resource expensive and doesn't scale. Instead m

1) Friendster had scaling issues. They insisted on keeping the x-degree-of-friendship-calculation which is quite resource expensive and doesn't scale. Instead making the software scalable, they brought in expensive exec who decided to through more and more very high end servers and enterprise storage on it. It eat their startup money, and they were constantly firefighting with very high page load time like 12+ sec, instead of advancing the site for at least one year. MySpace took over Friendster because of this. 2) MySpace culture and management was in trouble due Murdoch's News Corporation bought MySpace's parent company. Instead of investing News Corp choose the wrong path. Instead of improving the site, they decided to do a (in the end) very costly deal with MS to switch their ColdFusion stack from Java stack to dotNet stack incl very expensive MSSQL licenses and various other license costs. It turned out ColdFusion on dotNet was still in very experimental phase and MySpace suffered from the caused troubles a lot and bleed money like never before (which made News Corp very unhappy). MySpace website got little updates for at least one year while MySpace devs were busy with firefighting and switching backend. Facebook took over. There are books worth reading. 3) Stackoverflow (like 2 years ago) run on less than a dozen of servers. It's several magnitudes smaller than social network services like (former) MySpace, Facebook, Twitter, etc. License costs often don't scale, you bleed through your startup money for little competitive advanced features or return. That's why successful startups often choose open source stack, look at Amazon, Google, (former) Yahoo, Facebook, Twitter, etc. - Perl, Python, PHP, Java, Ruby, MySQL, Postgres, Hadoop, etc. Stackoverflow shows it can be done with off the shelf COTS as well, if you keep the server license count low by wise decisions and performance tuning. But it's not like I could name dozends of successful startups that have a software stack like Stackoverflow. And even Hotmail, Linkedin, Bing run or used to run for the majority of their service-live on mainly open source software stack.