If other people are editing a grid simultaneously with you, you'll see their edits in real time!

Why is this so cool?

Your tasks will always be up-to-date. No need to refresh your page, and you're much less likely to overwrite someone else's changes.

Do I need to change any browser settings?

Probably not.
The only requirement is to either be using a browser that supports web sockets (currently only Safari and Chrome) or have Adobe Flash installed (99% of internet users do).