Very recently (a few hours, if not sooner), a series of malicious/fraudulent short links ostensibly for acai berry spam but actually to allow hacking of Twitter accounts has been making the rounds amid the tweetstreams.
The recommendation is to NOT click on any links alleging anything (pros, cons, info, buying, etc.) acai berries and similar products.
Also, there may be an association between this occurrence and a series of hacked Gawker.com accounts spawning lots of fraudulent traffic.