It's something I've known for years and eWeek.com does a good job of highlighting. Opera is at the forefront of
browser innovation. Just off the top of my head, for me at least, Opera was the first browser I ever used that had: tabbed browsing, mouse gestures, MDI (multiple document interface -- when using tabs or not), inline searching, a plethora of customizable keyboard shortcuts, "real" cached histories allowing very fast "back" browsing, full page scaling (including graphics and flash), easy toggling of graphics on/off/cached, reload every x seconds, closed page undo, trashcan of recently closed pages to look through, notepad to quickly/easily jot notes while surfing, nicknamed bookmarks, and if I thought more than 3 minutes I'm sure I could come up with more... like author view, magic wand, linked pages, view links, favicons, quick/easy skinning, personal bar, small screen rendering, fit to width viewing, voice browsing, etc. That's not even mentioning pop-up blocking, browser ID spoofing to overcome numbskull websites dishing out crap for certain browsers, easy disabling for GIFs, sound, javascript, plugins, etc. I'm glad I didn't spend much more than 3 minutes on this list... ;)