Why make your own yogurt? Well, it's quite easy, you control what goes in it, it's cost effective, and you get to feel superior to everyone around you who lives a sad, store-bought yogurt existence. Besides, this yogurt has a very clean, fresh taste that I enjoy. The other day I canned some Clementine Marmalade that totally went awry and didn't gel properly so it was really more syrup than anything but I immediately knew that a spoonful of it would be quite pleasant in my yogurt. I often stir in marmalade, cranberry sauce, any jam, fresh fruit and/or granola.
One thing to note: it doesn't get super thick and has more of a soft set finish. I don't mind this at all but I imagine some people would. As an additional step, you could spoon the chilled yogurt over a cheesecloth lined strainer and let it drain over a bowl in the refrigerator to make sort of a Greek-style thicker yogurt.
Making yogurt is really just a matter of heating, whisking, pouring and waiting. All you need is milk, yogurt starter that you can procure from your local health food store or co-op, and a yogurt maker to incubate it, like this one which is a newer model than the one I have.
First, heat a quart of milk until it is just about to boil. Take off the heat, pop a thermometer in it and allow it to come back down to 108 degrees which is warmish room temperature. This will take a while so don't wait around. Pour a small amount of the milk into a bowl (about a 1/4 cup) and empty the contents of the yogurt starter into it. Whisk hard, you don't want any clumps. Pour this mixture back into the milk and whisk well again.
Second, pour into the glass jars and place into the yogurt maker. Set for about 8 hours and resist the temptation to lift the top, jiggle the yogurt maker, etc. It can't become yogurt if one keeps messing with it.
Lastly, put the top on each jar and refrigerate which then stops the incubation process. Done!