For people doing lots of searching (guilty!), this certainly appears to be a handy add on, allowing you to perform quick searches without having to leave the page you are currently on or the need to open another tab. Having a visual preview of the site before actually visiting it is pretty nifty as well.
Besides with a name like Yahoo Axis, who wouldn't want to at the very least check it out!
Has anyone tried it yet? Let us know your thoughts in the comments or over at our computer forum.