Haven't really seen any increase at all. It has been constant for the past 3 months.
I have had Adbrite on my site for a long time and was very happy with them until around 2 months ago when my earnings from them went in the toilet.
I never removed the ads as they were in the footer of my template on the proxified pages so wasnt in the way as the other 3 advertisers where doing fine so didnt want to look for a replacement
This week out of the blue my adbrite earnings have increased was wondering if anyone else stuck it out and now sees an increase in there earnings?
I've been in a similar situation - really good earnings up until October/November time, but a very significant decrease (2/3 ish) over the past month. I've not noticed any recovery yet, but I'm heartened to hear that things are improving for you.
I'm going to stick it out. I've got no complaints about AdBrite overall - they've always been fair with me.