He has no idea what git and github are, so the name gittip to him is just a nice, symmetrical name that has "tip" in it and evocations of "gift."
Go figure.
Look at the way that "bit" and "wiki" have evolved beyond BitTorrent and the WikiWikiWeb. I console myself by hoping that with gittip, the same is maybe happening to "git."
The main thing I'd worry about is people mis-hearing the name and trying to go to either gettip.com or gifttip.com, but it's very likely that I'm giving people too little credit. That wouldn't be a problem if 'git' enters the non-technical zeitgeist, but that's admittedly a pretty big 'if'.
That's about as good of feedback as you can ask for.
I think you're right. It's a good domain name and "regular" people won't pick up on the reference and won't really care regardless.
In my book, not exactly. It's more like the mildest possible term of abuse. You could generally get away with calling someone a git to their face and in front of their grandmother. Assuming they'd done something tricksy or cheeky or grumpy.
The mission statement gives examples of how this is a great idea for musicians, coffee shop owners, and other generally smart people ("genius grants for the rest of us"). On the other hand: the name, the required GitHub authentication, and the list of suggested tippees all strongly imply that this is solely for programmers. This says to me that the grand plan is to start out by focusing on programers (which makes sense, since it's a group of people who are on the whole really good at recognizing and rewarding people and projects that make their jobs easier), and to eventually expand from there.
The problem with this is that 'Gittip' is an incredibly technically-focused name; it makes perfect sense in context of tipping your favorite GitHub contributors, but not so much when your average non-engineer Joe wants to give money to the guy who makes his coffee every morning.