Big companies posting official job listings can make sure they comply with all of the relevant laws simply because they have HR and legal teams to do all of the legwork.
If you're a startup who really just wants a wide range of enthusiastic candidates to apply, you either:
1) Don't participate at all, lest you accidentally violate the rules or, worse, the law.
2) Post a huge range of salaries (This position pays $80K to $500K) so you don't exclude any candidates, but then your risk angering the readers.
3) Break every listing into multiple positions with different salary bands (Software Engineer I: $100K - $150K, Software Engineer II: $150K - $200K, Software Engineer III: $200K - $300K and so on). This barely provides any more signal to the reader, but it complies with the rules and laws.
Personally, I'd be most afraid of making it complicated enough that HR has to get involved. I'd rather allow engineers to post up generic invitations to apply to a company, not change the rules to require highly specific job postings or nothing.