Uh I don't think so. Not with a NTouch. I don't have one so I could be wrong. But I don't think you can.
You can, but only with content purchased from B&N.
I've never done it, though, so I can't tell you how...
You can only share quotes in books bought from B&N and downloaded automatically to the hidden partition. Books bought from B&N but side loaded due to space constraints won't be able to share quotes either. That said, it's easy. Tap and hold on the first or last word of the quote you want to share. The highlight feature will appear. Drag one side or the other over to highlight everything you want to share (note that you can't continue to the next page if your quote continues on). Then tap Share on the menu that is at the bottom of your screen.
Yes, but be aware that you'll be not so much sharing a quote with your friends as posting an advertisement for them to buy the book at B&N. In other words, the quote will get posted to your wall, but the most prominent part of the post will be a bold headline that links to the Nook Store.
Not very cool, IMO. I tried it to see what it would look like, and I won't be doing it again.
I've never used the function, so I haven't seen the exact format, but it seems a little naive to think B&N wouldn't use this as a marketing opportunity.
I have seen the similar-idea Kindle shares and I didn't find them anymore obnoxious than the other notifiers from stores/products/brands that I have liked on Facebook.
I can see how this type of marketing might be perceived as annoying or invasive. I see it as part of the "cost" of using free services and features on a site like Facebook. Now, if I was paying for my FB account out of my own pocket, I might get worked up about being used for someone else's profit. YMMV.
Just my 2 cents.