Does anyone have experience building up social media presences prior to the launch of a product/service? We know our target customer and target user (different in this case) and want to build an audience to inform upon launch.
Echoing Zack, I'd say target specific users if you can -- influential individuals you might write about you, share your content or otherwise support you when you launch.
To catch their attention, though, you have to first figure out *who* they are -- and drilling down like this can be challenging and time-consuming at the beginning. It's worth it to have that bang at launch!
One other tip -- consider guest posting on blogs that cater to your target market, and send readers back to an opt-in. Piggy-backing off other brands' already-established communities is often a quicker and smarter way than trying to grow your own from zero.