implement "border of privacy"

The distribution of Potentially Embarrassing sites for any given category has a very long tail (cf. many different niches in the adult category).

It's probably not feasible to statically list all of the sites in a given vertical, given that user behavior is likely to be heterogenous. Instead, if we can start with a small "seed list" and calculate a border of private browsing, that might be more likely to scale well. This only works if Potentially Embarrassing sites like to each other (which they may or may not)

For example, if a user puts "pokerstars" on the naughty list then it is possible that any site that the user navigates to within 2 clicks might also belong on the naughty list.

gregglind / blushproof

implement "border of privacy" #2