don't think you'll find one solid definition of MFA. Heck, I've got sites that I created because I could make money on them, and I've got sites that existed long before there was AdSense (or Google, for that matter). In general, when the ads outstrip the content, or the content is scraped or stolen from someplace else, I tend to think of that as "MFA" - but I don't necessarily think Made for AdSense is always a bad thing.
Yeah. I agree with most of this. I mean, what is another MFA - Made For Advertising or Made For Affiliates? Most of my sites for made for something. If you own a decent amount of them, you created them to make money and most of the time - ad money.
Having said ALL that I would say a "Made For Adsense" site in it's negative connotation (probably what the first poster is referring to) is IMO a site created to capture high volume or high paying keywords in adsense with little useful content around the ads for the average user. Basically gibberish in sentences to get high paying ads to show.