I don't think seeing ads helps your "market sense" or any other type of good sense. The ads are generally designed to make you spend money, and usually that doesn't involve making you smarter.
That would be like watching television commercials to learn how to make cars. It's not even good information on how to sell cars; most of car commercials are for cars made by companies going bankrupt, the last thing you want to do is copy them.
That doesn't mean that you might not want to monitor the ads your competitors are running and occasionally survey what else is out there; but in general, if an advertisement is spread across part of your computer screen, thebn fewer brain cells are working to make you money. Unless it is YOUR advertisement that you are working on, of course.
That would be like watching television commercials to learn how to make cars.
Well, it might be a little more like watching television commercials to be aware of what the typical experience of watching broadcast TV is like. A producer of television programs might do that from time to time, although perhaps not all of the time.
the number of maps that donated divided by the number of free users. It's not linear, though: there are months when I get a lot of donations (on various sizes). The smallest one being two cents (that was just once, though) and the biggest one having reached 120 usd (yay!!!).
The donations are also higher during specific periods of year (like christmas)
I would assume he's taking any obligations he has into account when he says 3-4 years. It's not like anyone would say "I have 3-4 years, except when you take into account my mortgage, kids, student loans, eating, bills..."
If you are really angry and want a refund, you'd better move your domains out of godaddy(I recommend Moniker.com) quietly before you do a charge back. You know domain name is your most important property so don't put any risk on it.