How to Spot the Resume of a Psychopath Applying to Work with You

I don't really think that's a fair statement. 6 seems a little high for 10 years, but in my experience changing positions every 2 or so years is par for the course for people who A) work hard enough to outgrow their responsibilities in that time, and B) respect themselves enough to seek significant raises every couple years.

If companies in general were in the habit of offering internal promotions it might be a marker of instability, but I've met few people worth their salt who will stick around at one company for 5+ years for raises that barely keep pace with inflation.

The article is obviously not talking about software developers. :-)

When was the last time you worked for a company that had any sort of training for developers?