The more you post, and the more topics you start, the more kudos you get. However, kudos is more importantly given and received by AA members. If one person thinks another has done a superlative job advising on an issue, he or she can donate 10 or 100 or 1000 or whatever kudos points. Theoretically, the more kudos you have, the move invaluable (valuable) you are to the site. Realistically, a lot of the most invaluable ppl are the ones with the least kudos, since they give it away most frequently. However, it is a way to lend credence to new members to the site who may have extensive knowledge, but may not have posted many times.
Me... I've forgotten about it entirely. I should start donating some!