Most bookmarks don't inform the site that you've bookmarked it, or let that site keep a very public counter of the number of bookmarks to it, or keep a public record of your bookmarks (delicious(however it was punctuated) not withstanding). It actually behaves very much like Tumblr's "Like" functionality in all of those regards.

I agree, it acted at least a little like a bookmark, but not more than it acted like a "like".