I think I've figured the root of this wildly inconsistent problem - I hope this helps others.
The tl;dr version: Your case and the way you hold your nook will affect your ability to swipe flip (among other things).
How did I finally get it to work? I took it out of the cover.
The Whole Story:
Since I bought my Nook about a month ago, I've only accidentally been able to turn the pages (randomly) via the dark touchscreen. I tried every method described in 6-7 different forums, blogs and documents. I tried it dozens of times, but it very literally never worked once. I sat down today and looked at the video of the lady expressing supreme disbelief about how it couldn't work for other people. I tried it "her" way. No, it didn't work.
I have the "Dillane Plaid" case; like many of its design, it has a leather cover and a plastic inner liner/shell/holder.
http://gifts.barnesandnoble.com/Dill...9781615598830/
When I take it out of the case:
- Swiping works
very casually, with varying pressures, angles, durations, locations, etc.
If I keep it in the case:
- Actions become less certain, and the swiping action must be a lot more precise
- Swiping with the thumb of the same hand holding the case, it works most of the time
IF I use a very light quick touch.
- A heavy dragging motion only works about 1 in 14 times.
- I must swipe somewhere in the middle of the screen
- The finger doing the swiping must be swiping before it comes within about 2mm of the screen.
Why does it behave this way? I don't know, but I suspect it has a lot to do with the capacitive touch screen. Something about the proximity of the plastic of the cover insides interferes just enough with the field of the screen to give it fits.
Oh yes, I forgot this bit: You can only turn pages of a book or magazine - the page flip will not advance to the next page in your My Documents, or My B&N Library, or anything else. Only "e-book" material. I mention this, because I didn't realize this and much of my frustration resulted from trying the swipe flip where the arrow buttons perform the same task.