No, ethanol is not methyl, nor is it isopropyl.http://en.wikipedia.org/wiki/Ethanol
2 cents worth of babble on the fuel itself;
Ethanol [corn squeezin, grain, etc] isn't the hatefully corrosive fuel that methanol is. Perhaps many of the wive's tales come from fellows that have been around methanol fueled racers. It must be flushed from the fuel system after running. If not, it'll turn aluminum to goo, and it'll ever etch cast iron cylinder walls. Not so with ethanol. Guys are running E85 and E98 [sold in barrels, like racing gas] with normal steel tanks, carbs, pumps etc. No problem letting it sit in the car. Many feel that it is a wonderful fuel for a high compression and/or supercharged engine, btw.
I know that small engine and boating folks are freaking out. Fwiw, here's my take on some issues when using ethanol laden fuel in older equipment [marine engines, lawn equipment etc];
One issue is it's ability to absorb water from the air. This may be worse with boats that sit on the water, esp those with open vented fuel systems. I would cap vent lines, use plastic sheet over the fuel cap etc on a boat that sits. Another issue is years worth of varnish in the tank, lines and carb in older stuff. At the onset of using ethanol laden fuel, that crud comes loose, and it will end up in the filter, and/or small orifices and carb bowl. Probably the biggest issue is the rubber used in older fuel line and many rubber parts in pumps, carbs etc is attacked by the ethanol. No easy fix there. The aftermarket is going to have to step up and change the "rubber" material. There may be some real issues with substandard castings made from junk, but "normally*, the metal parts are not effected by ethanol.
As far as mileage and tuning, as jpete said, it hurts mileage and will be worse at 15%. The stoichiometric ratio for ethanol is far different than for gasoline. Much richer mixtures are needed with alcohol fuels. Therefore, the engine isn't happy, although I doubt that any harm will be done to most normal vehicles, even at 15%.
Why does the fuel "go bad" quicker? Perhaps someone with more of a chemist backround can say. I don't know. I don't have issues with today's gas sitting for a few months, but I do know it will not last for years, like gas from "back in the day" would.
That said, imo, ethanol in this Country is illogical, and not about being "green", but rather greedy.
Edit; Check this link;http://healthandenergy.com/ethanol.htm