Just a thought:
underinformed.com works best for selling ideas (e.g., a blog that is meant to inform people about some issue)
justintroduced.com works best for selling products (either a specific product or else an ongoing list of newly introduced ones)
In general, I imagine that products have a higher profit potential than ideas ... so I like the second domain better than the first.
(Rough estimates: underinformed = mid-high XX, justintroduced = XXX to XXXX range.)
Regards,
Dave