Chrome: Ever read an article online, only to forget most of what it said a few days later? Hibou is an extension that will remind you to re-read it later for better retention.
Hibou uses spaced repetition to help you remember stuff you read. Just add an article to the Hibou extension, highlight the information you want to remember, and in a few days, it will remind you to brush up on that article.
If you're getting the hang of it, you can have it remind you less often, or if you still need a bit more repetition, you can tell it to remind you more often. It's a great little extension for those of us that end up in Wikipedia holes for hours on end, and don't remember any of it the next day.
You can read more about how Hibou works here, or check it out for yourself at the link below.