Unless you were living under a rock yesterday, you will know that facebook started the rollout of Timeline for Pages.
I think its an excellent update (pagetabs at 810px width anyone 
But thats not the purpose of this post.
Thew new timeline for pages will give us a very very powerful method for discovering the demographic of your target market.
Say your promoting a jersey shore offer.
1) find most popular facebook pages related to the topic:

Dont hit the results, go for the link at the bottom to show all results. This list is better sorted then the other one.
Then just pick one of the pages with most likes.
2) Check if the page uses the new timeline
After 30 march all pages will use the new timeline.

If not - go back to the search results and pick the next one
3) Click on the like count

4) He presto!!

We now know:
Its a declining trend -> 31 July was its most popular week
Its hottest in LA
18-24 year olds love this!
Now this is probably nothing new for you jersey shore fans.
But imagine what this allows you to do for more unknown niches 
Have fun!!!
I wonder how did you find out all these secret?
Tijn's got special connections. Thanks for the share as always!
That's great stuff, and being able to see where the majority of a fan page's users live is HUGE if you like fan page spamming 
Woohoo! just what I was wishing for!
Excited to use this..
edit: the bad thing is there is still alot of normal pages that dont have this, but will wait for March 20th