Pre-launch Marketing Strategy?

We're in the process of launching a "social contest and campaign builder" tech start-up, months away from launching in fact.

What pre-launch strategies have worked for your start-up? What are the do's and don'ts?
Looking for innovative ONLINE strategies. Outside of the common pre-launch sign-up page, blogs, and social media/PR.

Interested to hear what has worked for others!

EDIT: our target demo would be B2B.

You don't necessarily need to be innovative, you should strice for being effective. Chances are that by achieving the first you will also achieve the second, but as with everything innovative you run the risk of your measures backfiring.

Without knowing more about your particular business, it's hard for us to come up with something "innovative" (which sure is subjective too). If your product is good enough, you should be able to get enough people in funnnel, no matter how traditional your marketing measures are.

And while we talk about marketing measures: Why don't you just try to innovate the traditional ones? Make sure you don't have the boring "hey, here's my cool product give me your email adress please" signup page but make it a little more interesting. Like with a flashy :-) HTML5 animation etc.