Did Valve Just Out Half-Life 3 In The Steam Database?
The thing that's sparking all the Half-Life 3 hysteria on the web is a list of packages on Steam, one of which contains a reference to "Half Life 3" (without the hyphen). There's a website called Steam Database (SteamDB) that keeps track of these things, and it's been successful in the past in predicting unreleased titles.
At the the same time, it notes that a reference to a game doesn't equate to an outright confirmation of its existence.
"While this information comes straight from Valve and many of these kinds of leaks turned out to be real in the past, it is important to note that third-party Steam developers can create and name their own apps/packages."
They could also be old, outdated references of games no longer in development or no longer bound for Steam. It's happened before, most notably with Halo 3, which so far hasn't materialized.

While the "Half Life 3" reference isn't a confirmation of the game's development and upcoming release, there are reasons to be hopeful. First, let's talk about the missing hyphen. Well guess what? When Half-Life 2 made an early appearance in one of Steam's packages, it wasn't hyphenated either.
Secondly, a file called hl3.txt was recently discovered in a DOTA 2 update. Nobody outside of Valve knows what the file is for, only that its contents seem to make references to the Half-Life series.
Finally, when Valve added the ability to permanently remove games from your library by looking them up in the support section, SteamDB noted the presence of a Half Life 3 (again without a hypen) placeholder.
Are these a series of coincidences fueling a collective grasping at straws, or is Half-Life 3 finally on its way to becoming a reality? We fear it's the former but are crossing our fingers for the latter.