This service is a simple affiliate program for your site. No registration needed. Just publish the link of the form:
http://btcurl.com?url=<your url>&partner=<bitcoin address>
Users that click this link are redirected to <your url> and their unique visits are counted for <bitcoin address>. Everybody can replace <bitcoin address> with his/her own address to become affiliate. You can pay for attracted visitors with the link:
http://btcrelay.com?url=http://btcurl.com/visitors/unpaid?url=<your url>
If you don't hate frames, publish the link of the form:
http://btcurl.com?url=<your url>&frame&partner=<bitcoin address>
It enables visitors to submit their bitcoin addresses (see
example). Each submitted address counts for both visitor and affiliate. Use the following link to pay for attracted affiliates:
http://btcrelay.com?url=http://btcurl.com/affiliates/unpaid?url=<your url>
You might want to create a periodic paylist at btcrelay. Note: you won't be able to edit it, but you can always create a new one via modifying <your url> (e.g. appending it with "#<someid>").
Link:
btcurl.com