[Tossrock]

Even if a business has real revenue and real profit, there is still danger depending on the source of that revenue and profit. If there's a large downturn in the startup world, b2b/SaaS companies which profit from startups will suffer too. What will the effect to github/pagerduty be if 3/4ths of startups vaporize? "Not good", I would wager.

Ultimately, it's about the source of the money. SaaS companies are higher up the "trophic chain" than than the startups that pay for their service, but VC money can still represent a substantial portion of their revenue, just passed through an intermediate company first.