It is only recently, that the oral care community has begun to understand what these white spots actually are - many people have reported that their dentist told them that they were actually just extra food debris -
this is not true!
Tonsil Stones don't do any physical harm, and sporadically coughing them up doesn't mean that there is anything wrong with you. However they can be annoying (who wants to cough one up when they are kissing someone!), and sometimes they are an indication that you have bad breath.
If you have ever broken open one of those white tonsilloliths, then you know that they smell absolutely terrible! What you are smelling is actually a combination of volatile sulfur compounds(Methyl Mercaptan and Hydrogen Sulfide), post nasal drip, and bacteria (no wonder it smells so bad!)
They will only form in people who still have their tonsils, however that does not mean that you should run out and get your tonsils removed! Not too long ago, they were routinely removed for the sole crime of being swollen and inflamed. What was not understood then was that their sole purpose is really to prevent organisms and bacteria from traveling deeper in the throat.
Tonsilloliths are not something that you have to live with - there are various treatments to get rid of them, without having your tonsils removed (which can be dangerous as people get older).