I also built http://feedsub.com for RSS to inbox. There's better tools out there nowadays but I find it useful.

The site seems to be mostly full of advertising spam.

I've had this idea on a back burner for a while, however having looked at your site, it's clearly being used by people for landing pages that get linked to from spam emails.

If that's how these services get abused, I'm glad now I didn't waste any time on my version :(