As my dear friend Robin Adams (shown in 2nd screencap below) articulated so well - It's officially started! Facebook has officially begun integrating the "@mentions" Mashable reported on last week. Now, whenever you type the "@" symbol in a Facebook status update, you'll be given the option to "tag" one of your friends in the update. The feature already includes the ability to tag Fan Pages - an inclusion for which I applaud the Facebook team.
In case anybody doubted how quickly this new feature would catch on, allow me to show you the results on my own home page within minutes of its release:
Remarkably, I actually discovered this while publishing a status update for one of my clients' pages, and thus the only criticism I have of the feature thus far is the limitation of @mentions to your own friends versus your page's fans. Once Facebook finds a way to incorporate @mentions for Pages in such a way that allows them to tag fans of the page regardless of their personal connections to administrators, Fan Page virality is going to EXPLODE.