Late last year I wrote a short piece on some of the social media and other means online publishers could use for customer acquisition and content discovery. There are even more choices today. Pinterest seems to be an effective traffic-driver for fashion and design-oriented sites, but far less effective than Facebook or Twitter – which themselves, aren’t major movers – for news. Facebook’s latest move, a refinement of its Like plugin, is more geared to holding onto readers than finding new ones. Like Google+ and its own earlier efforts with companies like the New York Times, it aims to recommend to existing readers articles their friends read, without pushing that sharing or discovery activity back to its own site. And Facebook has always been a boom/bust partner for apps on its sites. Zynga partly blamed a poor quarter on Facebook promotional changes, but other social games’ traffic seemed to have held up okay.