[newlyretired]

Twilio has nearly a $3 billion market cap right now, and their signup/churn/usage rates give them a good idea on the growth potential for this market.

Nobody I know is a Twilio engineer, but nearly every backend developer I've worked with has, or wants to use, Twilio. There's something old school phreaking about using a computer to control phone systems.

They seem to believe that the market is very broad, occasionally deep (Uber was ~10% of their usage), and super cool. They haven't gotten so big to discard their focus yet playful roots (their hackathon outreach is a great example; that's where I first learned the API).