Site owners have to sign up for the service before participating. That barrier should be removed. For example, you should be able to flattr any URL, not just

Site owners have to sign up for the service before participating. That barrier should be removed. For example, you should be able to flattr any URL, not just web sites that have opted in. Here's how it would work: if you see a site that you wish to give money to, you would flattr the URL with a promise of money, but not real money. You would do this on flattr.com. The owner of the URL will go to flattr.com and see that they have $89.13 in "flattry" waiting for them if they sign up. At that point, the site owner has incentive to sign up and collect the money. Once the site owner has signed up, the users are notified that they need to pay (or payment is taken automatically). This way, users don't have to wait for a site to add the flattr button and site owners will have much more incentive to sign up once they see the money waiting for them.