Notification system needs better usability

Separate notifications into type (Comments, Follows, Favorites, Promotions) that I can isolate and examine them individually.

While I care about the others, as an artist it takes a lot of time to pick out comments from the other notification types. I need to be able to respond to each comment I get (or at least read them), while favorites and promotions could be summarized with a number, and follows could just be a user icon and name.

There is no reason these should be infinite scroll items (especially at 20 per load). It takes way too long to scroll through 200 new notices in the current system, especially when I'm just trying to hunt for comments to send replies to. It starts to lag sometime after the 4th load. Really I think infinite scrolling could use some optimization (I never lag this much on tumblr with it) and elimination in some areas (editing my gallery is a giant pain with it too).

Finally, I need some way to acknowledge and remove them. Notifications aren't something I need to keep around to scroll through later. Once I've dealt with them, a clean list, or at least a "mark as read" feature would allow me to separate new notices from the old ones.