Not every cheese is the same - they differ in terms of not just flavour and the milk used (goat, cow, sheep - unpasteurised, pasteurised) but how it is made and the aging length among other things.
Cottage cheese is cheese curd - the stuff that is left when you cook milk with an acid. It is not aged or coloured.
It's a good health food because of its low sodium and fat content, and is usually eaten with fruits, cucumber (tzatziki) or just cane/brown sugar. I used to eat heaps of this when I was in Switzerland and preggers.
For more info, check out Wiki's page on cottage cheese here.