"Sell anything" is probably a bit too restrictive, but summarizing case law on what counts as "affecting commerce" is difficult. In general, you need something that looks like a service or good being provided (even if no money is actually paid for it). Something like Youtube would absolutely fall under the ADA--it's clearly analogous to a movie theater.
Let’s just be honest - anyone can sue anybody, but you’re probably not going to have problems under the ADA unless you become visible for some reason (success, expressing the wrong thoughts loudly, service necessity for a community, etc).
