All good points. If you look online for industry-wide comparisons, you tend to find them behind paywalls. That's why I used SEC filings, which are public. It's also very tedious. I suppose that's why people think they can charge for having done it.

A list of "comparables" for Twitter might be hard to compile. If you take a really new company, of course they have to invest in R&D, a lot. Twitter really isn't coming out with radically new products, AFAICT.