[quote=@BBeast]
[quote=@Captain Jordan]
There's an idea. Have the buttons be [noparse][[@][Quote]] [@ Mention][/noparse]. If you get what I mean, no padding between the [@] and [noparse][quote][/noparse] so they appear to be two parts to a single button, making the [@] a mentionable quote.

It'd be no smaller than the rating buttons, so it's not exactly hard to hit. It preserves space. And being directly adjacent to the quote button, it makes it clear what it does. 

EDIT: Mockup, because I could:
[img]http://i.imgur.com/znKWy9j.png[/img]
[/quote]

Those buttons are rather close. For people who don't use a computer mouse (eg. all mobile users), clicking one button rather than the other would be tricky.

In regards to the discussion on notifications, perhaps a good middle-ground is to sort (and maybe even group into hiders, at least if there are more than 1 or 2) notifications by thread. Thus you do not increase clutter, but the notifications are still grouped into where they come from so you don't have a mixed list.

I also prefer full quotes rather than expanding quotes. Expanding quotes require extra elements on the page, thus more to go wrong, and the first few lines only provide the proper context if the first few lines of the post are the context and not a later part of the post.
[/quote]

They're really no closer than the ratings buttons are. And once a proper mobile implementation hits, the buttons should be large enough to hit with impunity. 

The benefit to mobile, however, is the ability to zoom in and be sure that you're clicking where you want. Google's Chrome mobile browser, additionally, will pop up a magnified version of the space you're trying to hit if it's not sure which link you've clicked. Between those two features, it shouldn't be too difficult.