Some providers offer the ability to upload. That said, it is potentially a risky action and most would suggest that unless you are very sure about what you are doing, and take proper precautions, it is not worth the risk for the average pirate. Providers get a LOT of DMCA takedowns, so unless you have something really obscure that you feel would be worth uploading, it probably isn’t something to attempt. YMMV.

A seedbox transformed torrenting for me, but now I only use Usenet for movies/tv and Mobilism & Anna’s Archive for mags and books.