The Meaning of Life, the Universe, and Everything.
This has about 50% chance of being helpful and 50% chance of being really annoying. By looking at the tags of posts you have viewed, it finds posts with similar tags which might be interesting for the user. You may be able to change the tags it uses to find suggested topics through the settings. You would type in a lost of tags, and if a post comes up with two or more of those tags, it gives you a notification and takes you to that post. You could also change how many of the same tags it needs before you get notified.