Linkshare has determined that only about one in 20 social media users interact with advertising. Banner ads are only clicked through by four per cent of users. That said, fewer than one in five consider advertising intrusive in that space. Still, only five per cent on Linkedin and nine per cent on Facebook felt they were useful.
Then there is a study from Pearanalytics that seems to play into the prevailing criticism of Twitter --- that it's a haven for mindless prattle. The report found little news on Twitter (3.6 per cent, in fact) and a lot of vents and blasts (40.5 per cent). There are plenty of conversations and a fair amount of promotion and spam in the mix.
(My own view is that, when you follow a good group, you get a good reading on Twitter's value. If you simply open up to everything, you don't get value for the experience. Twitter wasn't established as a news distributor, but as a conversational tool --- as a social medium, after all.)