Without judging it one way or the other, there is a certain mentality among many in tech (especially Silicon Valley) that jumping full-time jobs every 2 or 3 years is just how things are done. By contrast, in most situations, a resume with 10 different jobs on it tends to set all sorts of alarm bells off. It's partly a function of startups, which frequently fail. But it's not just that.

Well, a resume with 10 jobs on it is just a badly designed resume. Who cares where you worked 20 years ago? Drop in the three positions you feel are most relevant to this application, not everything you ever worked on.

This makes a fair bit of sense, but how does it fit with employers poised to jump on any career gap (which I guess you could say is a warning sign in itself -- but seems to be common)

One thought would be to do it like academics do with "selected publications" and have a section called "selected experience" or "relevant experience".

What I've done in the past though is simply mkae the older stuff increasingly terse to the point where the really old stuff is just the dates, company and title.

Do you want to work somewhere who thnga that your non-work 10 years ago is more important than your recent work?

If you're getting a clear demotion when you switch jobs, there's a problem.

Why is there a problem then?