This is an enhanced tag-cloud.
As usual the font, typeset and color are according to
each tag's relevance.
But, rather than having a tag-cloud randomly built, have
any tags that are connected between them (even via
other tags) closer to each other. And show a faint line
between them.
This line gives an indication of how
"close" the two tags are.
Then, when hovering on a tag, it "fish eye focuses" on
that tag moving the others away, and showing a faint
circle on it, with an inner slightly darker "focus circle" in
it.
If you hover over the focus circle it shows a new cloud
with tags that are connected to the current tag -- but,
perhaps, not originally in the set of tags shown before.
A set of options is shown for the hovered-over tag:
[strikethrough letter image] to remove it (if in a web
search it would mark search results as minus),
[-] to zoom out of extra connections, and bring back
original connections
[+] to make "more important"
You can also click on the lines, and make the connection
stronger, weaker or completely delete it.
A personalized version would save your preferences.
The public version may learn from the user's choices.