Summary of article from peteducation here: http://peteducation.com/article.cfm?c=2+2095&aid=1136

Mats are bunches of fur that get tangled together and are very common in breeds with long hair. If not taken care of they can get bigger and also become harder to break apart.

Avoid getting mats wet as they can become more tightly tangled. The best way to get rid of mats is to slowly break them apart using your fingers (if they are small enough) or a mat shredder if they get too big. One thing to remember is that dog's skin is much more sensitive and thinner than ours so we have to be careful with the pulling. Its best to grab the base of the mat and then either work it from there or start using a shredder.

Skin where mats have been pulling can become ulcerated and become infected. Since they are covered with hair we may not even know it! This is way constant grooming is very important. Most often serious mats have to be cut away so the best advice one can get is to never let them appear in the first place.

good info! mine used to get matted when he was a puppy..not anymore though..phew! they are no fun to get out!