It varies by company and era, but companies also pull a lot of citations that aren't really to the research content of the paper so much as to the mere fact that the paper exists, documenting that X was used by Company Y. (Academics also get a bunch of those kinds of throwaway citations, but I think it's considerably higher for citations to industry papers.) It's often useful if you're working in a theoretical area especially to be able to throw in a few cites of the "hey people really use this!" variety--- "similar ideas are used in deployed systems by Microsoft [1] and Google [2]" type things.
For example, if you were to look through the absolutely colossal number of citations that Google's MapReduce paper has gotten, the vast majority are supporting statements like "parallelism is important" or "these kinds of techniques are used in practice" or "a common current approach is". Not that it doesn't have a bunch of citations actually about the paper as well, but I'd suspect that it has more of these "free" kinds of citations than most papers do.
For example, if you were to look through the absolutely colossal number of citations that Google's MapReduce paper has gotten, the vast majority are supporting statements like "parallelism is important" or "these kinds of techniques are used in practice" or "a common current approach is". Not that it doesn't have a bunch of citations actually about the paper as well, but I'd suspect that it has more of these "free" kinds of citations than most papers do.