Comment by Leftium

I plan to use frecency in my bookmarking app.

Although you don't have any problems with lag, it is possible to efficiently compute frecency in O(1) complexity

> But with an additional trick, no recomputation is necessary. The trick is to store in the database something with units of date...

Full details: https://wiki.mozilla.org/User:Jesse/NewFrecency#Efficient_co...