I've been interested in the micropayments space for quite a while. The web is full of content that is great and helpful, but the barriers to actually paying for it are pretty high. Using something like PayPal, as many sites do, is problematic because PayPal's fees are high, and it takes a LOT of clicks (and typing) to make the donation.
My feeling has been that what we need is a company that lets you put a few dollars in an account, and then with a few clicks, donate a few cents to whatever you're interested in supporting. It appears, however, that someone has likely beaten me to the punch, at least potentially. Flattr is a recently released project based out of Sweden, which takes this Micropayments problem and makes it dead simple for the end user.
How does Flattr work? You begin by setting up a Flattr account, at this time either by requesting an invite or getting an invite code from a friend. Then, you seed your Flattr account with funds, it's worth doing several months at a time to avoid being too heavily dinged on processing fees. Choose how much money you want to give per month, from €2 to €100. From there, you just keep an eye out for "Flattr This" buttons, which you can see at the bottom of this post (and every post on my blog), or in my sidebar. Your monthly Flattr budget will be split evenly among everything that you've Flattred.
If you're a content provider, then Flattr does require that you Flattr things every month in order to qualify to earn any revenue, which I see as being more of a way to seed the system. However, I don't see it as a big problem, you should always be able to find something to Flattr. If there is a weakness to Flattr right now, it's that the Beta status, and particularly the slow ramp up of the invite system, weakens Flattr's ability to reach critical mass and usefulness. I've put Flattr up on my blog on hopes of earning even a small amount of revenue (my goal is to make my blog at least pay it's own expenses), however, I suspect most of my readers have never heard of Flattr, but even now, having read about it, that doesn't make it trivial for you to sign up and begin using Flattr.
Some people I've spoken to about Flattr feel that the equal disbursement Flattr does every month isn't ideal, they want to be able to add 'weight' to their Flattr's, giving some people more than others each month. Frankly, I think that overcomplicates the problem (Flattr only allows you to Flattr something once per month, that something can be a Blog or an individual entry. Flattring an entry doesn't preclude you from Flattring another entry or the blog however). The beauty of Flattr is that you just don't need to think about what you're donating. I've allocated €2 per month for the time being, and if I want to Flattr something, I don't need to decide how much to give. It's a one-click process, requiring no more thought than 'That was awesome, I want to donate to that.' It's this unthinking simplicity, and the ease of budgeting the static amount per month, that makes Flattr appealing to most users.
That said, I don't think that Flattr is the end of the story of Micropayments on the web. It seems great for many uses, but I think there is room for those more...thoughtful...disbursements where you do want to decide how much to donate. However, I think Flattr has a lot of potential, and I sincerely hope that they can continue to grow and thrive.