There is a great amount of information as proofs and definitions available on Math Stack Exchange. It will be really convenient if individual users can mark questions that they have read/examined separately. I feel that the ability to categorize questions as read/for later reference/etc should only improve the stack exchange experience. On the surface, I do not see any negatives to adding this feature, just that I do not have the necessary skill or editing privileges to add this feature. The only existing method similar to this feature is the adding filters part. However, it only deals with providing notifications on topics and does not help with the problem I mentioned.
You can already "favorite" questions. To do this, click the star below the voting buttons on a question. It should turn yellow, orange, or some related color depending on the site. Click again to "unfavorite", and the star will turn grey.
You can scroll through your favorites in your profile.
See also http://meta.math.stackexchange.com/questions/7156/how-to-personally-separate-questions-into-separate-groups-folders?rq=1 and http://meta.math.stackexchange.com/questions/8556/feature-request-hide-specific-questions?rq=1.
Please note: I'm not speaking on behalf of Stack Exchange here, just speaking for myself.
I like this idea.
It's been requested a bunch of times in our annual developer survey (and on various meta sites in the past), which suggests you and me aren't the only ones that like it.
Here are a few questions for you. If you (or anyone else!) have the time to check respond to them (comments are fine, or just email me — email's in my profile), I'd be grateful:
- Would those categories be just for yourself, or would you share them with other users? Why?
- When you look at a question you categorized, would you need to see your categories? If yes, why?
- Would you want to only categorize questions, or also answers? If both: why?
- What categories would you want to use (only the ones in the original question)?
Note that I can't comment as to whether this is feasible, and there may be some reasons why it's not desirable that I'm not aware of.