I think it was Chrome that started this stupid trend - the page title is only displayed in the tab, and the window title is empty. Now they all do it - IE, Firefox 4. It makes it impossible to see what page you're on when there are more than 5-10 tabs open, without hovering over each.
When I first saw this topic, I was 100% ready to jump in and adamantly agree. For me a dozen tabs in a browser window is a good start. But then I saw the part about IE doing the same seeming foolish blank title thing ... And it got me thinking...Does it?!?
Here's the thing, I saw the thread at work, where I use IE8, which still has page titles. SO I had to wait until I got home, where I use IE9, to see this with my own eyes ... And there were no titles.
...Now I'd have sworn, that I both used and depended on them. But the (apparent) reality is that I didn't even notice they were gone.