You are probably asking, "Why do I need a website to download torrents for me when I can just save them on my computer?"
The answer is simple, everything is moving to the cloud, especially media. I want a place where I can see my videos and listen to my music anywhere. You can convert your videos to MP4's and view them on your iPhone too.
You can subscribe to people and content too. I just setup my subscription for CNET's Buzz Out Loud:
They are even working on a Boxee app, which should be pretty cool.
Put.io isn't free, you pay about $10 a month for 50 gigs of storage and bandwidth, and they have plans above and below that.
There have been some free 30-day trials floating around on the web, but I haven't been able to get my hands on one just yet, but please send me a note if you are interested and I can hook you up.
Follow Put.io on Twitter too, for more news and info.
UPDATE: I have 100 trial invites for Put.io if you click this link.