Despite what happened to internet stocks in general, the right investment in a good scalable business model could still prove to be a great investment going forward. If you have a good understanding of a company's business model, you can understand how the earnings of a business respond to growth of the business. How does the company get paid when more of its services are consumed. There are many business models where the person receiving the value is not the one paying the revenues. Broadcast television is perhaps the best example.
TV is free, but advertising pays for delivery.
Although it seems like a simple concept, there were, and still are, companies that became public in the internet boom without well thought-out business models, scalable or not. Many internet business models didn't pass basic tests of credibility. The reason is that growth is entirely dependent upon increased page views, either by more users, or more pages, offset by declining ad rates. Both have upper limits, and most companies with advertising models have fixed costs exceeding current revenues. When you try to compute how many page views a pure advertising model needs to generate just to cover fixed costs, it is usually baffling.