Nearly enough Rated 4 out of 5 stars
This add-on lacks only one thing; a log file of the content of the drop-down tab which is presently the only way IPvFox reveals the URLs and IP addresses which the add-on collects.
Admittedly, these URLs and IP addresses can be highlighted and copied to the Clipboard with Ctrl-C [No right-click context menu copying with my copy of Firefox 11]; however, this is avoidably tedious and the copied text then needs formatting to separate the data into two field records for sorting and de-duping.
If IPvFox pasted the URLs and IP addresses into a log file along with the URL showing in the address bar, that would be a great help if someone wanted to be picky about which third party remote hosts were to piggy-back on calls to intended websites.
To be honest, I don't feel very enthusiastic about implementing logging to a file, because it's not a feature I'd ever use myself (and as with everything, I suspect it wouldn't be quite as trivial as it sounds).
Copying from the panel is definitely pretty broken though. A context menu would make that much nicer, and a "copy all" entry (that formatted things properly) ought to be helpful for you too.