Queue threads to view later?

[gdguide]

We have a "Level Showcase" on our forums where users post levels that they have made in a video game called LittleBigPlanet. However, there are many times when users cannot play the level, but would like to "queue" it to play later. Is there any addon that will allow users to mark threads to read at a later time? Maybe by adding it to a "To read:" notification?
If not, is there a way I can set this up myself?