[PopeOfNope]

you follow people within categories

One small nit pick: this is exactly what he's saying he doesn't want. He wants a way to be able to filter out content based on topic, not based on users. Putting a user in a category doesn't magically filter their baby pictures out of their discussion of algorithmic filters. Maybe automatic topic tagging? Combine that with being able to put topics on an ignore list and you would have my interest in a hurry.

[nip]

Following that user in "web development" instead of "everything" (a la twitter) will solve his issue. You follow people within categories, you don't associate people with categories.

I probably didn't phrase it correctly, I stand corrected.

When you share or save something on tree, you have to choose one of the 20 categories: tech, business, news&society, art&design, music, etc... In turn, people will see that you shared in X or Y and can decide to follow you exclusively in this X or Y category. Your feed is actually a multi-feed (depending on how many categories you decided to follow people in, up to 20).