This was generated with the LibraryLookup Project‘s Bookmarklet builder, which can build a similar bookmarklet for any library using one of 16 popular web catalog systems. Very nice. People are also turning these into Greasemonkey/UserJS scripts so you don’t even have to click; when the page loads, your browser queries the library and adds a link to the page like “This book is available now at the library!”. Some even report back how many copies at which branches, etc..
The great thing about bookmarklets and userscripts is that with a tiny bit of code you can force independent systems to work together for your benefit. Um..also because I can save these crazy YouTube videos the kids seem to love.