It seems that the initial reason for having the popup on SO is no longer an issue with the SO brand of sites - see the discussion below for more details. I suggest that SO either removes the popup-on-navigate away, or give us an option to turn off popups from SO.
I would rather live in a popup-free SO than what we have now, if possible. A long time ago, on a UserVoice far far away, I proposed that the 'navigate away warning' popup be removed. As I understand it, the popup was added because when you navigated away, you could lose the text that you were working on out of your history. (Now, most modern browsers don't wipe your forms when you navigate, but as I understood it, something in the back end of the site, under certain conditions, could make the form clear anyway.) The solution was to warn the user with a popup. (A popup, like most other popups, that was put in place of other, more integrated solutions. The best part? Someone chimed in during that post that the problem that caused folks to want the popup had been fixed, unless you had already made a response to that question.)
When I navigate away from a page, I do it deliberately. That's why I clicked on the link to navigate to another page. If I lose what I"m working on in this page, that's my fault, not the site. Making me click a popup when 99 times out of 100 I'm confirming what I already want to do makes me feel like I'm on vista. "You would like to navigate away from this page. Confirm or deny?" (dejected) "Confirm".
There was some...feedback. Of the static shock variety. Folks didn't seem to like it. Especially highly ranked SO members...I guess something about using a web form all day that eats their answers grinds on you, and a popup doesn't seem too bad. :) However, at the time, I had called for unilateral removal of the popup. This time, I think, just giving us the option to turn it off would be enough. All you have to do is throw this preference right there in the 'prefs' section, right under ignored tags, that says "disable navigate away popup". I'd check that box in a heartbeat.
Ideally, the solution would be to remove the need for the popup in the first place. For example, I just started editing this suggestion, and navigated back using my back button. I pressed OK on the the "I want to nivgate away" popup, then pressed forward. My edits remained in place, no problem. Then, I added more text, clicked on the "Meta stackoverflow" tag, and pressed back, and my edits still remained. If simply navigating forward and back were the root cause of losing edits, you guys have fixed it, and the popup is no longer even necessary! I'll try here, in a second, the multiple answer edit problem, and see if that's still an issue.
I've now done several bits of navigation after editing both questions and answers (and multiple answers) and every time my text has remained in the box after I navigate back. If text was being lost due to navigation at one point, it seems that defect has been corrected. If this was the problem the popup was trying to fix, it seems to me that the problem has been solved, and the popup can be removed entirely.
Can anyone else think of problems that the popup are preventing at this point?
Comments test followup:
I attempted the same tests as above, just this time with comments. I do not get the popup alerts when I entered text and then tried to navigate away...it looks like IE and Firefox forget the comment text on navigation. Chrome, however, remembers. (Go google...)