It is true - as a part of H1B application you need to post a job advertisement in some US job board first, which becomes a part of the documentation you submit to USCIS. I went through that as a part of my own visa process.

EDIT: ok, maybe my immigration lawyer was a weirdo :)

As someone who's gone through both H-1B and PERM, H-1B only needs the company to prove two things, specifically about how much you're paid:

The actual wage: This is the wage paid to other employees in the company who do the same work.

The prevailing wage: This is the wage for that occupation in the geographical area.

See: https://en.wikipedia.org/wiki/Labor_Condition_Application##1... https://en.wikipedia.org/wiki/H-1B_visa#Labor_Condition_Appl...

> as a part of H1B application you need to post a job advertisement in some US job board first

No, this is only part of employment-based greencard (LC) process. For H-1Bs, as part of the LCA process, the employer needs to advertise that a candidate is going to be hired.

Why not? Seems entirely plausible.

There's no need to speculate on "what's plausible" when it's a documented process: https://news.ycombinator.com/item?id=24703643