ARM valuation, great! Intel valuation, great! App with 500-million users that has no link or correlation to the POET marketplace at all.... not so much.
You have a point, but even though you may find it an apple/orange type of comparison, what I think is being suggested here is not a comparison, but a sense of potential moral outrage. As in: if a company that makes an application that merely augments Facebook is valued at $19 billion, then of course, it SHOULD be plain to see that a company whose technology will affect the entire computer and software world (including Facebook and everyone that depends on server farms) would be immoral to value at less than that, even if it is in the nature of business to do all it can to acquire assets on the cheap.