Opera browser 1994-2014 - Another Kind of Obituary - Episode Two

Since last week we talked about some general facts regarding Opera including its layout engine that made this browser special today we'll move to another field where Opera led the pack but as usual was severely underrated - its innovative features. Before moving on let me add one more thing - in most cases people may go "Hey but there's a Firefox extension for that how's Opera so special?" and from a certain point of view this may be the truth - there's nothing special about Opera features that are available as addons for other browsers but isn't it much better to have it all available right out of the box? Opera Speed Dial & moreMost of these features are not in such a close connection with the layout engine so after moving to the new layout engine that everyone will be using in a year or two people who use Opera only because of them should have no problem in keeping their favorite browser around:

- Tab stacks: a lot of Firefox plugins allow users to organize tabs and even more Mozilla introduced Tab Groups - but Opera was surely the first to have such a feature

- Opera Unite: speaking for myself I always found this pack of tools buggy as hell but I also must admit that I kept using it despite all its issues hoping the torment would end one day... but not as it did with Opera completely removing its all-in-one file sharing (and more) power pack...

- Personalized keyboard shortcuts: for me the standard keyboard shortcuts are usually more than enough but I happen to know a few hardcore users that really enjoy using Opera like madmen so they end up using at least 20 custom keyboard combos or so. Surely not the guys to mess with in a Mortal Kombat competition...

- Opera Mail: used it loved it and hated it at the same time but now all we can say about it is unfortunately Rest In Peace...

- Opera Turbo: not such a big deal if you got a decent connection but a great aid when you're connected via rather slow 3G modem as it happens when I am visiting my parents. In such cases there's no need for benchmarks the difference is there you can actually see it/feel it.

- Opera Notes & Opera Link: they have one big thing in common despite the fact they're different - you can sync your work with Opera's servers and various other devices using Opera. Awesome enough? Surely not something unique but why use Evernote or others like it when Opera offers everything right out of the box?

- Opera Speed Dial: no need to say more about it since it's simply awesome!

These being said there's only one question re... well two questions remaining: which one of these features would make you keep using Opera no matter what's beneath its hood and most important of all what did I miss? I know for sure there must be something awesome that Opera brought into this world and I'm missing it but I'm sure you can help me recall it (no it shouldn't be HTML5). ;)