May 2014 – Minh Le has seen things
Counter-Strike mastermind Minh Le told goRGNtv that he'd seen Half-Life 3 concept art, and the game is in fact being worked on! Sort of, anyway. More precisely, he said he saw something "that looked kinda like in the Half-Life universe," although he seemed surprised that anyone would be interested in such a thing. It also wasn't clear when he'd seen the material in question, since he'd left Valve several years prior to the interview. He was also clearly far more interested in Left 4 Dead 3 than anything to do with Half-Life. Thanks for nothing, Minh.
October 2014 – A bad idea
The "We Want Half-Life 3" Indiegogo campaign wasn't a Half-Life 3 hoax or broken promise, just a monumentally bad idea. Basically, a couple of advertising types decided to crowdfund a harassment campaign to let Valve know that people really want them to make Half-Life 3. You know, in case that wasn't clear. They asked for $150,000 for their campaign (which, in their defense, they later clarified was meant to be a one-day lark rather than concerted stalking); they closed with a little shy of $1600.
June 2015 – Another fake site
Sweet Aunt Petunia, a Half-Life 3 logo actually appeared on the Valve.Software website. Unfortunately, that site is not actually related to Valve Software, but for a few delicious hours (or minutes, depending on when you heard about it and how innately suspicious you are of such things) we could let ourselves believe that the light was finally shining. The site is still up and the HL3 logo still there, but the fine print makes it clear that it is "just a joke site." Half-Life 3 hoaxes are no joking matter, Timmy.
October 2015 – Dota 2 discovery
A file named hl3.txt was found in a Dota 2 update, containing references to "Combine Pulse Ceiling Turret" and "NPCs that are in the same squad (i.e. have matching squad names) will share information about enemies, and will take turns attacking and covering each other." That's straight out of a Combine soldier AI script, but what's with the hl3 filename? Valve maintained its usual stony silence, but I think it's worth noting that a year later, Gordon Freeman still hasn't appeared in Dota 2. That has to mean something.
Jan 2016 – Confusion on Reddit
Drama in r/HalfLife, billed as "possibly the first legitimate Half-Life 3 leak." What's interesting about this one is that as far as I can tell, nobody is entirely, 100 percent certain that it was a hoax. The information provided was deep, detailed, and not at all flashy in the way of most other gag teases, and its veracity was backed, in ways he couldn't or wouldn't make clear, by the forum mod. Eventually, the whole thing just fizzled out, without the usual "lol suckers" flourish at the end, which could be seen as further "proof" that the leak was real. But probably not.
February 2016 – Virtual teasing
The innocuous-sounding SteamVR Performance Test software, an app intended to determine whether or not your rig is up to the strains of virtual reality, is found to contain some Half-Life secrets in its code, including a high-quality 3D model of Dog, the super-strong, ball-fetching robot from Half-Life 2. Half-Life 3: The VR Experience, perhaps? Not likely: The software contained material from other Valve games too, including Left 4 Dead and Dota 2, and writer Chet Faliszek was quite clear on the point when asked about it last year. (He said "No.")
August 2016 – Gamescomedy
Right there, large as life and side-by-side with Titanfall 2, was a poster proclaiming, plainly and boldly, Half-Life 3! And some fine print underneath, which might have been missed at first because the poster said Half-Life 3! Except it was actually Half-Life: 3, as in, "Half-Life: 3 editors who played it back then." It's not so much a hoax as a lazy gag, but we all spasmed reflexively and so it gets the credit.
And that brings us to today, at least until the next joke, leak, hoax, apparent ARG, or off-hand comment. We give it at least 24 hours before that happens.