Investors need to understand that internet application service providers aren't software companies, and that it isn't reasonable to expect software-company margins (selling CDs for hundreds of dollars) from services providers.
Companies like New Relic, Twilio, etc. have real costs to operate their infrastructure, especially so in Twilio's case where they likely have to make payments to the downstream network operators (not sure on that last point, I assume, but would love to be corrected if I'm wrong)
But not many that have such a ridiculously high PE ratio. One of the main reasons tech businesses (specifically SaaS) can command such a high valuation is because their gross margins are amazingly high (some up to 90%, on average around 70-80%), which means 90% of their revenue can be reinvested back into growth (S&M and R&D). I think it's certainly fine to discredit Twilio when looking through the lens of publicly traded SaaS businesses (they're on the low side of gross margins), but if you compare to other industries, you're right, it's a very healthy business.
Good read on this:
http://tomtunguz.com/not-all-revenue-dollars-are-created-equ...