According to a Valleywag tipster:

FYI - I've heard the word from my peeps over at Yahoo Search Marketing in Burbank CA that the layoffs are going down as we speak, and people are being let go today. They're apparently walking the people into a meeting room, and then walking them out of the building.

And according to an SFist tipster:

[Layoffs will] occur over the next few days as employees are sent packing. Lots of security on campus and weird vibes around the place. This from someone on the inside...

Is it a total bloodbath? Or just a minor cleansing? And which tipster is sexier? More to come.