Great!
I don't suppose the license will be a problem, but you're right, should be verified of course.
A Flattr button on your site is basically like another "donate" button, but with big plusses. For donators the global Flattr service is much more interesting than separate "buy me a beer" or "donate" buttons. And as a concept, as a system or network, I love the Flattr idea. Makes use of internet power to link people...
The great thing about Flattr is that, as a donator, you can set your total monthly donation limit, say for instance €10 (or dollars or whatever), and just go clicking away on anything you like (provided it has a Flattr button). At the end of the month, your 10 bucks are simply divided between everyone you clicked on.
I, for instance, would like to set aside € 10 a month for supporting things I like, (a.o. Inkscape of course
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) but I want to choose who I support on the go. So I throw some funds on my Flattr account (say € 50 for 5 months), and then click away on Flattr buttons without thinking twice. The rest is automated, and I know I won't loose more than €10 a month.
Things I really want to support systematically, I can subscribe to (click twice on the button), which means Flattr will "auto-click" them once at the beginning of the month. Unsubscribe is easy also.
And if I don't want to Flattr anymore, I can pause or stop easily... Just cancel subscriptions and don't click on Flattr buttons, and my Flattr funds remain as they are.
I think every creator, and every person who likes supporting creators (even with microdonations), should be on Flattr. Anyone can be an art/open source/... patron now, with microdonations, and the service is really a plus (as explained above).
So everybody on
Flattr! (I'm sorely missing Flattr buttons to click on actually
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hence my publicity here.)