DeleteMe collects your information then does searches for that info against the databases that power all the online "people search" websites. If there are hits, they pay to have them removed.
If you don't renew your account, they just delete your data.
Edit: Looks like they also publish guides on how to do it yourself, that's actually kind of helpful. I guess the high price is to have someone continually checking and submitting removal requests on your behalf.