they avoid some problems by requiring everyone to pay directly. Megaupload really got into trouble for their affiliate programs, which essentially paid people to upload pirated content. Those programs drove a whole industry in Vietnam.

They clearly keep track of unique torrents across users because they provide the instant download feature. Thus they should be able to respond to DMCA requests quickly. By the same token, they may come under legal pressure to disclose user information about accounts that accessed successfully DMCA'd files.

There are legitimate uses for Bit torrent though, and this service seems like it would benefit the health of ecosystem as a whole. They'll probably seed a lot of data, maybe especially rare data. That would be helpful for things like big scientific datasets that often end up hosted on some .edu FTP site.