Now this really is a fascinating new wrinkle on the idea of search, at least academically. Bamber Gascoigne, whom the older amongst you might remember as the original University Challenge quizmaster, has not been sitting on his hands.
Instead, Timesearch (timesearch.info, if you want to remember it) lets you search by topic, and more importantly lets you filter by year. You begin by selecting an area (the world/Europe/Asia/Africa/etc... including subdivisions of those areas) and then a theme (all, arts, literature, performing arts, politics, religion, science, society, technology, war - and those too can be subdivided) and, if you want, a year or time period. Various timeline sites then appear too. (In concept, it's a metasearch engine, pulling together results from other sites but presenting a rather good face.) It's easier to use than to explain in words, to be honest.
Certainly searching by time - rather than by "reputation" - is something that one would never have realised that the web was missing until it came along.
It's surely going to be a very valuable resource for anyone who needs to do some studying and pull together a timeline, or link events in time. It's not a time for soundbites, but I can see the search engine of history in my browser window....