As soon as your Facebook page gets closer to a milestone, Facebook will prompt you to promote it more. Marketing on Facebook is not about likes but the total number of likes does provide an opportunity to page administrators to shoot for.
Matteo Gambo of Wimdu was prompted by Facebook to promote his page, at it was approaching 80,000 likes. Here's a screenshot:
Have you received similar prompts from Facebook on approaching the milestone figure?Facebook Asks Admins to Promote Pages as They Move Closer to Like Milestones!,