What is probiotic yoghurt?

A good question (put up by Suki in my previous post): what is probiotic yoghurt?
Well, it is also the yoghurt that you make yourself at home. Yes!
This word is important only for those who buy readymade yoghurt from the market. Because, with the non-probiotic ones which you buy in the market, they do a heat-treatment which kills a large portion of the bacteria, to make their shelf-life longer. The bacteria are still there, but in trace amounts which isn't really as beneficial for the body as the untreated yoghurt. The probiotic ones are a lot of times made with special bacterial strains, which are good for the body, but are commonly found and also present in your yoghurt. I remember that from my practicals we did with home made yoghurt at the university during my Masters.
The word probiotic is used for bacterial starins which are beneficial for the body.
Here is one wikipedia link, if you want to know more.
Another interesting read in daily mail about the real facts about probiotic yoghurt.