they're mostly automated, all in house, and probabyl trade closer to 2 bil shares a month than one. Getco LLC.
I'm sure they're up there in terms of liquidity providers, but not at the top. Nasdaq website now releasing a monthly list of leading liquidity providers, an interesting list, inclused nasdaq, brut and inet.
It's under trader news, I think....
as far as a website, I think you're right, but not having one isn't exactly for lack of publicity, these days. Sometimes better to have one to handle the incoming round of weird phone calls, etc.