Points to the efficacy of using Twitter to sell anything, I suspect. Sorry to hear about those totals, though.
Almost all of Musa's sales were dire. I really feel for all of its authors. I also sympathise with the people behind Musa who set out in good faith, and obviously worked hard to make it the best it could be. The problem was that its business plan was flawed: if they'd taken on fewer books, and focused more on each one, rather than trying to produce books in bulk, I think they might have done a lot better.
Moving on: Twitter can work really well as a sales tool where books are concerned. I know: I've seen it done, and I've been indirectly involved in several campaigns there. But a strong, well-structured Twitter campaign does not involve getting authors to tweet endlessly about their books; nor does it involve getting all of a publisher's authors to co-promote. It needs people--writers and publicists--who are genuinely engaged with their followers, who sign on to Twitter regularly and have a lot of fun there, and who talk relatively little about their books. Send out a whole raft of review copies to your Twitter followers and if they like it, they'll tweet about it, and their friends will hear about it, and the word will spread.
All you do if you're banging on about your own book all the time is alienate people.