I used to tell people a lot about my plans, even if they were just newborn ideas with exactly one (1) doodle to show for 'em. But I don't like doing that so much anymore...it gives me the appearance of someone who's working on lots and lots of projects, with all the pressure that goes with it. ^^; And I'm already actually working on lots of lots of projects; I can do without the illusion.
I try not to announce anything until I've at least thought about it for a couple months, and/or started a Word doc where I write down all my ideas (if the inspiration fizzles out immediately after I start writing, congrats, I get to keep the project under wraps for a little longer).
Sometimes I dream about starting a comic where I don't even tell anyone it exists until I've drawn at least a few pages in preparation...sigh, one of these days...