You're forgetting hashtags. We saw similar things happening in the Australian election, where Twitter shills and bots (acting primarily for the Labor party, which appeared to be a bit more switched onto social media overall than was the Coalition) were used not only to spread messages, but also to retweet favourable messages (sometimes posted by themselves, sometimes just ones from the general public) so as to artificially promote certain messages to top tweets for the #ausvotes hashtag.

A quick point of fact. The letter listed Rahxephon, however only the Rahxephon TV series and Movie have been licensed for English Language distribution. None of these were available on AnimeSuki. The Rahxephon OVA however, which was not licensed, was. Following AnimeSuki's compliance with MediaFactory's request, it has now been removed from the AnimeSuki listings.