There is a good thread over at Digitalpoint discussing why some people are still using the "aff" abbreviation in their Google Adwords copy when its no longer needed. One of the members is seeing this practice still in place and trying to determine the incentive from doing this. According to 5Star, "They just don't know any better. Some people just don't keep up with the news and missed that whole big change." I can't say I noticed it exactly the day it came out and I watch a lot of the news. There are a couple of other reasons why a person would still use the "aff" in the ad. One, they do not want to disrupt their CTR of the campaigns, or the placement. Additionally, some advertisers are required by the affiliate company to use this particular branding. I don't know many that do, but apparently their are some. Another reason, might have to do with the url. I just searched on affiliates in Google and one of the first ad has a nasty "?afid=AFX1DNQ7889" affiliate id tag in the url. Now, maybe I am wrong but if you are trying to target savy webmasters to become your affiliate, and you are using a url like might raise a few red flags for stay away.
For continued discussion see Digitalpoint - "Aff." in ad copy?