"We Are Not Announcing Half-Life 3"
Valve will be making an appearance at E3 this June after last year's hiatus, making many of us wonder whether they've primed a reveal or two. However, according to multiple sources, they'll only bring already-announced titles to the party.
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).
Newell recently admitted that Half-Life 3's development cycle was taking longer than expected due to continual changes to the design, and that they're not willing to announce anything until they're good and ready to avoid disappointing the fanbase.
On the other hand, this is exactly what you'd say if you were planning an enormous surprise reveal, but I wouldn't suggest holding your breath.