[Sigia-l] more info on hover

[Stephanie Hornung]

i'm noticing a lot of site these days are giving users more info  
about an object when they hover over a link or image.  has anyone  
done any user tests on how effective this interaction is?  it's  
similar to a tool tip, so its not so new, but it is new on the web.

here are some examples:

http://www.netflix.com/BrowseSelection?lnkctr=nmhbs
  (hover over the title or the image for a movie)

http://a9.com/sanka
(hover over over the site info image)

and of course, google maps:
http://maps.google.com/maps? 
q=coffee&ll=37.798691,-122.407362&sll=37.786014,-122.399030&spn=0.029060 
,0.052878&sspn=0.030592,0.055661&num=10&start=0&hl=en
(click on the tack on the map, to get info)

these are all in different spaces, and in some cases i think its more  
useful than others (i.e., the google one works, not sure about a9).   
any opinions?

thanks!
stephanie