The team I know at Adobe has invested a lot into HBase and they are offering their services globally. But according to this PDF, in a true polyglot database manner, it looks like other parts of the Adobe business have opted for a different solution: Cassandra. The size of the cluster mentioned in the whitepaper is pretty small, 16 nodes, but what is interesting is that these are beafy servers using solid state drives:
The PCS is comprised of large servers using solid state drives (SSDs) for storage […] The PCS is basically Cassandra with a set of custom APIs built on top of it.
Original title and link: Cassandra at Adobe: The Profile Cache Servers ( ©myNoSQL)