Earlier today, it was noticed by those at NeoGAF that Valve has indeed filed for a trademark on Half-Life 3.

In addition, a tool used by Valve to show which staff are assigned to which project was discovered as being public just about an hour ago. The tool showed that 46 developers are assigned to Half-Life 3 with 71 developers assigned to Left 4 Dead 3.

Things are getting exciting now!