Well, it looks like it might have just been wishful thinking after all. We recently reported that a Trademark Filing appeared on the European Unions Trademark Site, OHIM, with the owner listed as Valve for the name "Half-Life 3". Searches on the site now turn up nothing.
The trademark filing had been listed on September 29th on behalf of Valve Corporation by a patent and trademark company called Casalonga & Associés. Going to the site now and entering "half-life" in the search area only returns the original two entries for "Half-Life". Entering in the trademark number that was assigned to the Half-Life 3 trademark returns "Unsuccessful search: Found 0 trade marks." The United Stated Patent and Trademark Office site does not show anything different either (there never was a trademark for Half-Life 3 on USPTO).
So, was the trademark filing a fake and they pulled it when contacted by Valve, or is there some other reason it was removed? Perhaps Valve is getting it ready but wants to kill any hype so they can announce it in their own time and manner? Perhaps Valve is just trolling everyone for lulz?
We all love a good conspiracy theory, so feel free to post your ideas on what you think is going on in the comment section.
[Update] A trademark has appeared on the OHIM trademark site for Portal 3, so perhaps the company which originally filed for Half-Life 3 on behalf of Valve just got the game's name wrong, or perhaps they are really hoping for the next Half-Life game too. Again, there is currently no corresponding entry for Portal 3 (or any Portal games for that matter) on the USPTO site at this time.