What are your thoughts on tabbed browsing? Do you find it improves your productivity?

I've used a tabbed browser for a long while now. It's great for navigating through sites quickly, building queues of links, and for keeping track of multiple sites (e.g. webmail, banking, Backpack). I also find it hugely valuable when searching; much faster to filter through results. And I'm a big fan of tab sets.

But I do question whether tabs let us overload ourselves with information. Tabbed browsing is another form of multi-tasking. Does having many tabs open at once mean we focus less on the content of each?

I admit, my attention span isn't terribly long and I tend to skip between tabs. Does anyone here find it more effective to just use one window at a time? Are you able to focus better on the task at hand?