this way:
I do provide Feedbeat free for private, non-commercial usage since I do believe that is is good to do so. I also do hate advertisements. If you do think that this is a good attitude and you do want to encourage me to keep this philosophy up, I will gratefully accept any support. And nowadays the easiest way to support in general is to donate. Sad but true.
I am a self employed consultant and programmer. My company consists out of me and my coffee-mug and so does Feedbeat. If you do find this constellation evil in any way you really should not donate.
Please keep in mind that Paypal grabs approx 3% (or so) for their clearing services. E.g. 1$ is a very nice gesture but on my end of the funnel their will be an amount which will be that small, it will be eaten by its own bank transaction and may leave a hole in the space-time continuum.
Furthermore you should keep in mind that I may terminate or alter the service at any time. A donation is a donation. You do not gain any shares or similar. Its just a very nice gesture of you. So please, please do not give an amount that forces difficulties or embarrassment.
Common standard procedure: I will use it to buy a bottle of red wine. I will take this wine into a park. I will sit down in the sun there and think about the good in man and have a good time.