DigitalOcean makes pretty extensive use of ads for retargetting & etc. Try going to their site then browsing Youtube or Twitter, for example. I've seen enough of the "You've been coding like a beast..." video to last me several lifetimes.

Content marketing into emailed drip campaigns and/or retargetting is a pretty powerful formula in many SaaS businesses. Scalable content creation can be a pretty powerful force multiplier at lots of businesses, including SaaS businesses.

A service which is remarkable enough to mention to friends, or which intrinsically gets mentioned to other people in the course of typical use (e.g. Basecamp), is a nice asset to have, too, but many SaaS companies grow without those advantages.