A screen-captured email requesting Half-Life 3's announcement at E3 with Gabe Newell responding that Valve would not be announcing any new products has been officially confirmed. Various outlets have confirmed the email's authenticity with Valve.
Here's exactly what Gabe's email response said:
"We are not announcing anything at E3. Really. We are not announcing Half-Life 3 or Portal 3 or Left 4 Dead 3. We are going to be showing stuff everyone already knows about (CS:Go, Dota 2, 10' UI, ...)"
This announcement comes as a small contradiction to statements made last fall promising all of our, "favorite things," to be announced at E3 2012. While expecting a Half-Life 3 announcement might be too much, the lack of any game announcements is rather surprising -- and disappointing. Then again, Valve has lied before.
What will be shown at E3 is still, well, nice. Steam's "Big Picture" system sounds spectacular in theory, and feature details at E3 would be a grand thing. A potential release date announcement for Dota 2 might also be coming, as the beta is is quite robust. It may not be up to Valve's unwritten standards, however. Heck, why even both speculating? Valve is crazy and who knows what they'll surprise us with.
Still, this is a sad day for PC gamers. Mope, mope, mope.