One interesting difference: Google just uses for their buttons instead of tags or even . They also don't set cursor: pointer (the hand) for them. Any UI people want to comment on the best practice for cursor styles? I always figured pointer should be used for all buttons or links that have an action attached.
Well, the old technical limitations of the web have muddied the affordances somewhat, but my rules is generally "add cursor:pointer if the button behaves like a link, leave it unchanged if the button behaves like a button". Most of the G+ buttons actually behave like buttons , i.e. you click on them and something happens on the current page. They don't have cursor:pointer, but they have other standard button hover ef…
Just because browsers didn't do that in the past for form buttons doesn't mean they did the right thing.