The best metric I've seen for exchange volume is Coingecko's:
https://www.coingecko.com/en/exchangesAssuming you have a pool of accurately reported exchange volumes (not every exchange fakes volume), you can get a fairly good estimate for a site's volume based off its web traffic. Exchanges that have much higher volume than their web traffic suggests are consequently adjusted.
So liquidity can be faked but web traffic can't be done so easily?
Everything can be faked, we have fake yt,fv,tw profiles with thousands of web followers, how much do you think it will pump 100k visitors?
Besides, similarweb si a piece of garbage of its own when you go and get stats country by country you will see hilarious rankings, just take a look at Japan or Saudi Arabia., this is because they can only get data from the sources who are willing to tell them (and which can obviously be fake) and from users who install their extensions or app, which again is 1002% biased.
Yeah, liquidity can be gamed, but it comes with a lot of problems, you can't put fake walls continuously and either take hits during dumps or annoy customers that their trade orders haven't been executed or were so at 10% difference. You can fake activity when bots play for a billion 1 cent trade, but what will you do with a fake wall when somebody really wants to dump...take the hit or execute the trade till zero?
And also, after 50 exchanges, liquidity is non existent. How many "exchanges" are there?
Too many...
Every time I visit the reputation section and I see somebody unable to get his money from one exchange in 99% of the cases my first question is, "how the hell did you manage to find this one?", let alone use it and get scammed.
Maybe this new index will be like a serious slap from reality and common sense to some, but ....I lost hope.