Yeah whatever happened to all of those?

Whatever happened to Basecamp itself? I used to hear about it all the time...

Last I heard they had 6 million active users (vs 1 million in 2012).

... by what definition of active, and what definition of users? Surely you would define such a SaaS by revenue or number of customers rather than users, which allows you to fluff up your number by claiming every individual at every client organization is a user ... even if those accounts are automatically generated by some onboarding process then ignored.