Say, what if someone made something like GeoHack - MediaWiki but for protocol handlers, and had ties with the ad industry? Seems like a good way to collect a whole bunch of data - after all, protocol handlers don’t work on mobile, like, at all, and even if they did work, if the desktop UX is anything to go by, it’d be a pretty crappy experience too. Not only can a third party service provide a better user experience than existing browsers, but it can also mine all the data in the process! That seems bad!
(past discussion: Meta tag for protocol handlers default )