Twitter which was once plagued with outages every time anything happened seemed to retire the fail whale recently, survived two national political Conventions, four Presidential/VP debates and a Canadian election. The new election page was very cool. Participation is way up. CNN has at least two of their anchors on twitter (here and here) and day by day, twitter is closer to becoming a household name.
Maybe investors with the economy the way it is, investors want to see their investment make some paper.