Monetizing the anti-niche

So. I tend to create websites inspired by an idea, providing some sort of tool for users, and typically not driven by making money - though one has a strong revenue stream and does well. Aaanyway... I remembered one of my sites which has been running on autopilot for three years and thought I ought to look in on it.

To my surprise it's getting more than 40,000 visits a month. It's a light-hearted tool for Twitter users, so the audience is inherently general (and probably doesn't hang around for long).

What are your bright ideas for monetizing this? These occur to me:
- bog-standard AdSense or maybe ClickBank HopAds. (The site reads people's Twitter profiles so in theory some basic targeting to their stated interests is feasible.)
- sell ad space, eg through BuySellAds - but who is the audience? (Or just aim for widely popular subjects such as weight loss or making money?)
- sell the site on Flippa to someone more enterprising than me (I'm reluctant as this site feels like an old friend - admittedly one I've neglected)
- possibly I could sell data from it: it has more than half a million records based on around 25,000 Twitter users' data (ie individual accounts are analysed more than once), which could be of interest to someone...?

Or is this destined to be a victim of the common mantra at WF that there's no money in Twitter-related things?

Your thoughts are welcomed!