Update: It seems as if we were duped. The trademark filing has since been removed , suggesting its initial listing was a hoax. Original story below.
Here's some small news about the obscure indie collective Valve, and their potential follow-up to cult hit Half-Life 2. The game/Steam/OS/virtual hat makers have filed a trademark for Half-Life 3 with the European Office For Harmonization In The Internal Market. Before you travel downtown to GIFtown , note that this doesn't really mean much beyond the fact that they've decided to protect the name Half-Life 3. In fact, perhaps the biggest news here is that, before this, Valve didn't have a trademark for Half-Life 3. Dammit folks, we could have made it ourselves!
The trademark (search "012180394" to see it for yourself) is categorised as "video game software", suggesting that Half-Life 3 could be a game, and not, say, an official Gordon Freeman announcer pack for Dota 2. Really, though, we're in the same place that we were previously: assuming that Half-Life 3 is being made, but not knowing anything beyond that.
That said, NeoGAF, who also discovered the trademark , did some digging around JIRA - Valve's internal tracking tool - and found a Half-Life 3 project group currently comprised of 46 people. They also noticed a Left 4 Dead 3 group containing 71 people. Again, it's by no means confirmation, but by all means treat yourself to a mini freak out.