Microsoft (originally Micro-Soft) is a portmanteau of microcomputer and software.
Facebook, as others have mentioned, is a compound word that was borrowed from what literal books of faces [and names] were called.
When I think of non-dictionary names, I think of things like Mosptnspg.
Hard disagree. Consider "Oracle," a truly inspired name for a database company. It's an admirable choice. Here's the computer science definition.
> In complexity theory and computability theory, an oracle machine is an abstract machine that can query a black box called an oracle, which is able to give an answer to any instance of a certain problem in a single operation.
There's also the wealth of linkages with classical oracles, e.g., Delphi, Cumae (technically a Sibyl), Dodona, etc. [1] Taken together, it's hard to think of a better name.