Icons : Key words on hover?

[lollobrigida]

I know that there are certain layouts that in comments when you hover over a user icon either just the keywords appear, or the name and keywords for the icons appear.




in Robber's Daughter by roniabirk



in Non-Customized Pages for LJ

Is this sort of feature possible to get on customized pages in Expressive? Even if it's in a theme layer, or a layout code?