looks like easysocial doesn't support joomla's native page class setting - here tested on the group category layout page: http://screencast.com/t/AADL7mUU
unfortunately this setting has no effect at all, the class "whatever" is not inserted, so it can't be used for further actions.

I also tested this with easyblog (frontpage layout), here it works fine: http://screencast.com/t/8r5K7XbXPfo
it also works on native joomla articles: http://screencast.com/t/YywdFGSoa4j

so something you might want to look into