It'd be an interesting way to count how many impressions your tweets get: add a URL to every tweet, put a tracking "pixel" in the webpage (assuming the webview loads all assets; if not, then just add the "pixel' URL to the tweet..

There's an impression counter on every tweet, visible to everyone

All ad networks also claim the ad you pay them to show got n impressions, according to their calculations, here's the bill...

Make the pixel a zip bomb for lols

Advertising landing page full of CPI ads?

Is the request coming from the user's IP or via a Twitter proxy?

As a plain webview would mean that you can grab everyone's details.