I remember reading one of Scott adams' blog posts that wanted an app that worked exactly this. I'm afraid it'll be too impractical for any real use. I'm curious

I remember reading one of Scott adams' blog posts that wanted an app that worked exactly this. I'm afraid it'll be too impractical for any real use. I'm curious though. How woul it be able to tell the contents of, let's say, a sub just by looking at it? Edit: typo fixes. Trying to catch up on feeds before I sleep with Reeder, works great except for the damn auto correct on the phone.