Nice experiment. A couple bug reports: The Tip button doesn't work in IE. And, I found TechCrunch on the list of the sites twice!!! One with www. and one without it.
I also have a few bug reports:
- while signing in it said that my email-address was already taken, and did I left my pwd blank. Highly unlikely and no.
- in safari I can't move my cursor around in the email-address field because you jump to the end at each keypress.
The twice-techcrunch is because it was submitted twice in a particular fashion. I'll merge them shortly. They've both gotten a bunch of tips, but only one is available on techcrunch.com. It's actually an interesting accidental experiment to see the tipping rates.
And the tip button doesn't work in Safari either. Are you developing on Linux? ;-)