By seeding a copyrighted file, someone could get Amazons IP address, who would in turn know the data was hosted by Put.io? I doubt they could get out of DMCA that easily.
Put.io reuse download content amongst all its users. It's only present on the network for a short period of time. Because it's a paid service, actual usage is quite small compared to all regular users combined, so they would not get much attention.
