user can simply donate to the website by clicking on it (which will launch bitcoin client with pre-filled address).
See URI scheme, BIP 21:
-
http://en.bitcoin.it/wiki/BIP_0021Example:
Creating and parsing "bitcoin:" URI Strings:
This is the easiest part, which is fully-documented in
BIP 21: URI Scheme. Here a simple example of how you would include it (using my donation address, of course!)
<a href="bitcoin:1ArmoryXcfq7TnCSuZa9fQjRYwJ4bkRKfv?amount=1.0&label=Armory%20Donation%20Address&message=Donation%20to%20Armory">Donate 1.0 BTC to the Armory Project!</a>
...which looks like:
Donate 1.0 BTC to the Armory Project! Yea but that's just a URI link to open someone's local wallet. Adding a metatag opens the doors to more possibilities and layers on top. Like OP stated browser extensions. In the distant future when bitcoin is widespread the metatag could be scrapped by google's robots and added to results. So if you search for "Brooklyn Cupcakes" you'll receive all the matches, plus they could use that metatag to indicate they accept bitcoin.
Brooklyn Designer Cakeswww.designercakes.netWe offer and makes amazing cakes for everybody, order today with Visa.
Matty's Magnificent Cakeswww.mmcakes.ny BTCI make all my cakes by hand with natural ingredients. Come down and visit us and try our coffee. Free wifi!
Mastercard Cakeswww.mastercakes.usWe are really old and do things the old way. We only accept cash and mastercard. Newspapers also available for $1.25
In the above example Matty has the bitcoin metatag so he gets a little
BTC by his search result.