There might not be any official word on Left 4 Dead 3 and Half Life 3 but fans believe Valve will look to introduce and release either one of them soon. Question is which one?
The recent leak revealing Valveās internal database can be a useful source of information. Looking at the mailing list in the database, Valve is known to employ about 300 staffs. Out of those 300, 42 of them have been getting updates regarding Half Life 3. The 42 are employees who are developers and designers.
This is a huge number and is bigger than those seen working on Left 4 Dead 3. This strongly hints on Half Life 3 coming soon. In addition to that, the new Source engine is nearing completion and fans are hinting that Half Life 3 will be the ideal launch title for it.
Knowing Valve, that is unlikely. Left 4 Dead 3 is the more realistic target for Valve. After all, it could be that the game developer would want to give Half Life 3 the best launch yet.