With tabbed browsing becoming such an important part of life, how should applications be developed so as to give best experience to user?
Second big problem is: How do we manage so many tags? For a moment, consider tags to be bookmarks. Each tag vies for our attention. While in most cases tags are temporary "handles" for helping us react to large amount of information, the actual attention span required might be quite large.
For example, workflows might involve a sign-off from co-worker, and all this while, you might want to keep the tab open (rather than remember to open the application again, or get notified by email.)
Some contexts might be really long-term: I might want to track a discussion, or wait to see if someone is selling that iPod at pricepoint of interest to me.
So as we don't have a decent notification system in place, I think tabs should get an important status.
Or perhaps merge PIM systems and tabs. Let one flow into another. And did I say that Email clients will greatly be helped by tabbing too?! (Incidently there is a slashdot discussion: Firefox as Platform. )