Guys who designed the LMAX 'disrupter' for Betfair have a good talk about how much trading these betting sites do per second <a href="http://www.infoq.com/presentations/LMAX" rel="nofollow">http://www.infoq.com/presentations/LMAX</a> and how concurrency is a major issue, Erlang makes sense even if they have to search for replacement devs