This Firefox add-on supplements missing pieces of information directly into the text being read, aiding comprehension.
And in case you are still unclear about something after reading, AQwikWiki has got you covered with its nested feature. But that's not all - AQwikWiki offers support for several languages, including French, English, German, and Spanish. You'll never be lost in translation again with AQwikWiki.
Version 0.1.16: N/A