Patent wars are a tech-company rite of passage these days, and now Facebook can say it has joined that expensive and catty club with the counter lawsuit it just filed against Yahoo. After Yahoo hit Facebook with a classic patent infringement lawsuit last month, Facebook has now accepted the duel. "From the outset, we said we would defend ourselves vigorously against Yahoo’s lawsuit, and today we filed our answer as well as counter-claims against Yahoo for infringing ten of Facebook’s patents,” said Ted Ullyot, General Counsel of Facebook, according to  AllThingsD's Kara Swisher.

Swisher has the full claim over at AllThingsD. But as far as we can tell, this is just another one of those money-sucking spats tech companies -- ahem, Apple and Samsung -- get into these days.  "While we are asserting patent claims of our own, we do so in response to Yahoo’s short-sighted decision to attack one of its partners and prioritize litigation over innovation," continued Ullyot. As for Yahoo, having just announced a round of layoffs, the company doesn't really need a lawsuit with an up and coming super expensive company now. Have fun, guys!