The Oxford English Dictionary (OED) Online web site has been completely revamped. You'll find it quite different from the old site in many ways (new design, new functionality, etc.), but with a strong element of continuity in the form of the editorial content.
The site has been tilted more towards the English language than towards the dictionary as an end in itself. Search results move from simple lists to visualizations/timelines. They can also be filtered according to a number of categories, allowing you to start off with big numbers (e.g. all English words derived from Italian), and reduce them by steps down to small, significant subsets (e.g. all English words derived from Italian from the field of Music which are first recorded in English in the 18th century). That's 167 words, starting with adagio.
Other new features include pages (updated each quarter from the dictionary data) on the OED's most-cited authors and texts, plus links to other online resources—such as the Oxford Dictionary of National Biography—offering more on those who've shaped the language. There's also an ‘Aspects of English’ section, a series of descriptive articles on language, past and present, which will be updated regularly.
Perhaps the most important new feature involves the Historical Thesaurus to the OED, published in book form in 2009. The entire text is now integrated with the OED Online, so that you can follow semantic links throughout the dictionary. Go to the OED's entry for utopia, for example, and follow the Thesaurus links to the entries for heaven (Old English), Cockaigne (c1305), El Dorado (1596), nonesuch (a1618), Fiddler's Green (1825), never-never land (1900), the Big Rock Candy Mountain (1917), etc. ‘Utopia’ means different things to different people!
As ever, the core of the dictionary is its content. But with the new web site this content is opened up to an extent we couldn't imagine ten years ago when the OED first went online.