[Nook Color General] woot1524:
1. Is there any likelihood that B&N will or could in some way use this update (or any update) to prevent subsequent rooting or other hacks?

To be honest, maybe. But, once you autonooter or install a custom rom B&N cannot OTA update your nook.

2. Are all the various mods reversible? Our concern is being able to, at worst case, revert to stock in order to have all original Nook functionality restored, including brick-and-mortar store compatibility (e.g., in-store borrowing) and especially warranty service.

Yes, there are flashable images that will revert the nook back to out-of-the-box state. look through the Dev forum.

3. Regarding the B&N store, the AutoNooter threads recommend registering with B&N before beginning any changes. Is this necessary, and/or absolutely required, and why? If you register and then root, will that allow you to purchase books, whereas you would not otherwise have been able to?

I think it's something to do with being able to connect to google's services. yes it's necessary when you stay with eclaire, not wirh froyo/CM7/honeycomb. yes, the store works with rooted eclaire.

4. Is there a substantive difference (look, feel, or function) between the process of buying books on the original stock NC versus installing the Nook app for Android on a rooted or modded NC?

you use the store the same way on a rooted-stock nook as you would on a stock one. I don't know how the look feel or function is for the b&n app, I have an original nook for reading.

5. If one "merely" roots the device and doesn't install CM or NookieFroyo or other ROMs, can one still install apps at will? I'd be fine with sideloading if no Market app were functional.

The market works with rooted-stock, but you'll eventually want to install CM7 or Honeycomb, trust me.

6. My impression is that the stock NC supports very few applications but that with the upcoming upgrade B&N may be featuring a store. Is it accurate to say that in its stock form the NC is not (yet) much more than a book reader?

A stock NC is pretty useless for anything other than reading/web surfing

7. Regarding AutoNooter, it seems to have forked based on the 1.1 B&N update. Is it better to start at 1.0.1 with the original AutoNooter or to allow the 1.1 upgrade and use the GMPower fork?

Auto-nooter 3 works just fine for 1.1.0 thread: http://xdaforums.com/showthread.php?t=942424

8. Is an AutoNooter or other rooting procedure required before CM is applied? I assume so, but only ask because the CM procedure at Cyanogenmod.com (I can't post links yet) doesn't have a rooting step. Maybe it's the case that AutoNooter is for rooting the existing B&N image but that other ROMs can be independently booted from SD? (Told ya I'm a newb.)

No, you do not need to root to install Froyo/CM7/HC. The nook is hard wired to boot the SD-card first if able. You can go straight from stock to CM7 with one flashed micro SD-card.

9. What, if any, of the stock device's capabilities are lost (reversibly or irreversibly) by rooting and/or modding? (One I wonder about is in-store "free" reading at B&N locations.)

This I don't know. I don't use the NC as a reader at all. My Original nook takes care of that.

Hope this helps. Happy modding.