Ok. There is some confusion so one always refs google and or wiki. Supps sites, inc mine, can and do use common terms and recognized names for marketing purposes.
Caesin is the slower more milk like part of milk also described as 'curds' in the rhyme line about little Miss Muffet (remember 'eating her curds and whey'). Whey was the clear fluid. Both forms, as is, would be of piss poor to a bodybuilder as they need filtering and processing to enhance their digestibility and protein content. This gets done and you get a nice 'slow' protein (in terms of absorption etc).
Explaing the difference CNP explain it thus http://www.cnpprofessional.co.uk/blog/?p=185
stating 'Micellar casein is casein in its natural structure and caseins and/or caseinates are the non-natural, less bioactive forms. 15 years ago, the term “micellar casein” was born to try to differentiate the natural, bioactive form from the artificial, curd form of casein.' The blog entry is dated 2007. GNC/Reflex states 'Reflex Nutrition's Micellar Casein is an instant mixing time-release protein product made from fresh skimmed milk. It is not to be confused with acid casein or caseinates which are made using manufacturing processes which can denature the protein. The protein found in Micellar Casein is un-denatured, providing approximately 80% Casein protein and 20% Whey protein.'
Caseinates are listed in several ways (sodium caseinate, calcium caseinate for example).