I dont like the idea personally. I will never announce a project until its in a fully playable state and I have made atleast an alpha release of it. In that case you already know the project exists. Sometimes I wont announce until its 100% complete.
Announcing a project gets peoples hopes up and then if you take too long, run into snags, or just decide you want to do something else, you completly let down everyone who was counting on you to come through. You then have people asking you "when is it going to come out?" , "why isnt it done yet?" etc... etc...
Now if this was a little more specific, and about projects that _have_ already had a release, then I could see it working out. But if its about projects that are being worked on or designed, works in progress without an official release yet, etc...I would seriously advise against it.