The media are often... how should I say it... a tad behind the times in regards to how the internet works and how it can be exploited. For example, note all the media coverage a year or two ago about 'fake reviews' on sites like Amazon and Yelp. These have been widespread since both sites begun, yet were pretty well ignored by the media for most of that.

Or the comments and articles about Reddit's launch. Apparently, the idea that someone could use fake users to start a community shocked a few unwary people (and journalists). Despite this being a forum building tactic since the internet begun, and a business tactic (to some degree) for decades or centuries.

Or heck, the 'trolling' and harassment stuff about Twitter and social networks. Old tactics and behaviour, but seemingly not known by the mainstream media till it affected sites their journalists used.

Really, the media is unprepared for a lot of stuff, since they're about two decades behind when it comes to knowing how technology and culture works.

As for when sophisticated Twitter sockpuppetry would start having an impact? It might well already be having one. I mean, similar stuff is endemic on Russian language forums and sites, and hey, governments have access to these techniques and useful software to help carry them out...