Floating Rules for Blacklists?

[ArminF]

Pro's,

please enlighten me about these floating rules.
I could not get much out of it now but thought i might use them for importing the URLs tables from some blacklist sites and setup and bi-directional "drop all" rule for it.

Would this make sense at all? As far i understood the rulesset the default none rule would already be a drop/deny all rule.

thanks for your help!
A