I think this changed in the last few years. I used to remember the home page not showing adverts until a year or two ago. I'm not certain though. Doesn't bother me - as I spend most of my time on the forums when here anyway.
I used to contribute and let it lapse. Probably should again. Not sure I want to though due to recent treatment. I love MR, however lately the microscope is not evenly in its application and some of its use is beyond ridiculous.