"The Twitter ecosystem values learning about new content," the study notes -- so new info, it seems, is new info, regardless of who provides it. And sharing your own work conveys excitement about that work -- which means that self-promotion, rather than being a Twitter turn-off, can actually be an added value.
...This may seem like overthinking it; spontaneity, after all, is a big part of Twitter's charm. Still, it's also worth noting that, in the study's sample, respondents considered only 36 percent of the tweets on display worth reading -- and another 39 percent barely worth the effort. "These results," the authors note, "highlight the need for better awareness and presentation of valued content."