The main arguments against there being a bubble seem to be that things aren't as obviously a bubble as they were before the previous tech bubble. This is all a businessperson's approach to analyzing this situation.<p>Looking at it from a technical perspective: there are two kinds of companies out there. There are companies that do something people care about and ones that don't.<p>Think about Twitter for a second. If Twitter dropped off the face of the earth, would you really care? I wouldn't. Even if I used Twitter, it wouldn't be hard to just go find all the same people on Facebook or whatever and follow them there. People and companies use Twitter for self-promotion, but that puts Twitter into the same business demographic as a TV channel that runs infomercials. Some people watch infomercials, but if the entire infomercial market disappeared, nobody would really care. The problem with Twitter isn't that they can't monetize their product, it's that they don't have a product.<p>Then there are companies that actually have a product. They may not charge for their product, but if they did, people would pay for it. Uber and AirBNB charge for their products.<p>Duolingo doesn't charge language learners, but they probably could: my experience is that they are more effective for language learning than Pimsleur, which a lot of people pay for. It's an artifact of the Google age that companies don't actually charge for their product, but charge for ancilliary services around it. Google doesn't charge for search: they charge for ads. But if Google decided to start charging $10/mo for search? A lot of people would pay it.