Three weeks ago, it was widely reported that an analysis by PeekYou concluded that more than 90% of Newt Gingrich’s 1.3M Twitter followers were fake accounts, probably purchased to make him appear more popular. Further analysis by Topsy supports Newt Gingrich’s assertion that his Twitter followers were real people and that his campaign did not purchase any.

“Former House Speaker and GOP presidential candidate Newt Gingrich was correct in his explanation for why he has relatively few active accounts among his 1.3 million Twitter followers, an analysis requested by Mashable has revealed.

The initial analysis of his followers was apparently based on a a few trivial features, mostly the fact that the vast majority of them were inactive. But most of his followers came from the early days of Twitter when Gingrich’s account was on Twitter’s short list of suggestions for interesting people to follow. Mashable says:

“So there is no smoking gun to suggest that Gingrich, or any of these politicians, bought any of their followers. But what this kind of analysis also reveals, says Topsy, is how hard it is to say which Twitter accounts are for real and which aren’t. Spam bots are getting more sophisticated; many now have fake profile pictures, fake bios and generate fake tweets. “The fact is, a large proportion of all Twitter accounts are inactive anyway,” says Ghosh.

Sorting the humans from the fakes is a problem that companies like Topsy — and Twitter itself, which now has more than 200 million accounts — will be wrestling with for years to come.