the best way to do this is perhaps to add information to the blockchain that all front ends can go and take a look at and recognize what preferences a user may have. Then that front end may or may not even impliment those features. How many front ends would actually do it? It puts a large burden of UI work and also work to make a UI search for and save those settings and I'm guessing slows down the UI because before they display the posts they would have to check against the list of what should be filtered out. Maybe something could be done at the API level. Not sure.

Also it may be worth waiting to see how communities solves this by compartmentalizing topics and groups of people with similar interest.