That's a legitimate concern though. People have unoriginal broad ideas ("I want to sell stuff through app/website") and supply over-reaching NDAs ("_everything_

That's a legitimate concern though. People have unoriginal broad ideas ("I want to sell stuff through app/website") and supply over-reaching NDAs ("_everything_ mentioned is covered, with no expiration date"). Even if such is ultimately not enforceable, it could still be a major legal pain, if during your lifetime you get to work on a project that also implements some type of "selling stuff online" (see Lodsys' troll patents and legal pursuits).