who scaled out first, who'll scale out next
Well, no matter who came first, HP will be owning the "extreme scale out" concept from now on, for sure, thanks to the best server marketing machine on the planet and to faithful HP brand champions like Matt.
The fact that IBM announced a very similar product over one year before HP http://www.theregister.co.uk/2008/04/23/ibm_idataplex/
and the fact that Dell had an OEM server product which served the same segment (described in a BLOG they now unfortunately removed) will become irrelevant.