Rated 4 out of 5 stars

So the new URL Flipper will now remember all patterns, across different browser windows and sessions.. What about privacy? What about if I visited porn galleries and don't want anyone to know? I'd suggest to add a button 'remember this' like a whitelist of pages and patterns to remember.

This review is for a previous version of the add-on (3.0.1.2). 

UF3 will *never* store the actual URLs and patterns that you encounter. If someone breaks into your computer, ransacks your profile, and steals your URL Flipper pattern database, it would be impossible for them to extract any sort of history data without brute-force trial and error.

This protection is inherent in how UF3 handles pattern data: instead of relying on the patterns themselves, UF3 remembers only a cryptographic 1-way hash of a pattern, much like how passwords are protected in modern operating systems by storing only their cryptographic hashes. Thus, the only way any private information can "leak" out is if someone is visiting a site that you've remembered the pattern for, in which case they would be able to increment/decrement without going through pattern setup first. Once again, aside from a brute-force trial-and-error matching of every possible URL pattern hash against the list of stored hashes, it is simply impossible to extract arbitrary information from the stored data.

PS: All UF3 data is stored locally in the user profile. UF does NOT use (and has never used) "cloud" storage.

PPS: The "Clear All Pattern Data" command will permanently delete all accumulated data.