I've got the Similarweb Chrome Extension installed to give me stats on other web pages and got around to trying it on touchgram.com.
Which, promptly informed me we were too small to have been noticed but I could give them access to our Google Analytics.
There's also Alexa and Quantcast, based on the obviously-biased Quantcast page
The appeal in being listed is if we are to get on investor's radar, these are standard tools. However, I'm worried about privacy implications if this adds further burden, implies policy rewrites or just abuses our user privacy further.