Enlightenment's Terminology[1] supports a few fancy things including image previews, animated cursors (nyancat is a builtin theme...) and local file links. More impressively, it actually works really well, it's native, and it's fast (even hardware-accelerated). With all of that fanciness, it renders text even faster than suckless' st with a GPU.
Because it varies widely :).
It is entirely based on your query -- whichever source is detected as best for that type of query (i.e. Yandex is better at handling symbols, Bing's advanced syntax is better [mostly]), and of course it changes over time as rules are tweaked and added.
In the very beginning, Gabriel was more focused on the instant answers and hadn't thought much of privacy -- users brought it up after he launched it on HN.
1. Region can be changed in DuckDuckGo's settings, for more localized results -- by default it is set to "No region," so there is nothing localized in the results.
2. Bing is one of very very many sources, which are all remixed and combined, so the end result is completely different from Bing or any other upstream source (and most often, far better).
3. No, no, no. Nothing at all is sent to bing other than a plain request for an ad coming from DuckDuckGo servers with the query (for a page-relevant ad).
So, this sentence: "user agent (which I can assure you, it does get sent to Bing)" <-- Utterly untrue.
Now, when you click on an ad, naturally your information is sent to both bing and whatever site the ad was for. That's to be expected, you are leaving DuckDuckGo at that point. This is also true when you click standard result links, of course.
Now that that's out of the way, my personal opinion of result tailoring/bubbling is: it's good sometimes.
I love being in my cozy little bubble when searching for coding things, and even local businesses and such. I do NOT love bubbling when I am doing academic research. Why would I want to see content I already know and like? That invalidates the point of research, and even gives me a false idea about whatever I am researching.
Bubbling and tracking, while good in some cases, should be optional in my opinion.
Not sure what you mean there -- these are two completely different things. That disables using a service (Google or Bing) to autocomplete. It does not affect what extensions like the DuckDuckGo one do.
There is nothing malicious going on there. It does that so you can get instant answers where there would normally be auto-completion. This is covered very nicely in a paragraph in the addon's description, and can very obviously be disabled in the addon's preferences.
They exist for sites you've never been to before, you don't have to do anything to a fresh browser install to make them work, they are browser-indepenent (I don't use or like chrome personally), and you can use them on any computer at any time. I know they are always helpful for me when using public computers.
Fixed in Python 3, but still. There are more of these things.