This is for international publishers. As what do you classify the income from advertising? I deposited a Valueclick check today and the teller had to fill in a form and asked me what the purpose of the deposit was. I explained that it was for advertising revenue from a website, but the teller couldn't understand and just wrote "refund". Very strange since it's most definitly not a refund. I must also add that she didn't know what Google is or that ZAR meant SA Rand (on the Google check).
Well, probably you encountered a bank teller who is not verse in the goings of the internet. I guess it is understandable. I guess you could consider it as 'advertising income' or 'income from services rendered'.
This incident brought to my mind a friend of mine whose bank (a Citibank branch) didn't want to take Google's check for Adsense revenue fearing that such company may have not funds, LOL