Other Websites

I'd like private tutoring!
Wikipedia is one of the most popular websites for researching things that students do not initially understand. The content is of course aimed at a general audience, so it is often too detailed or unsuitable for A level.
Recommended for: quick definitions and descriptions, diagrams, connections with other subjects e.g. chemistry
Not recommended for: revision, learning the specification, extra reading material

Got a suggestion or want your website here? Tell me.
The Student Room is an active collection of forums designated for students of GCSE, A level and university, that cover a broad range of topics from exams, interviews, health&relationships, general, politics, to fashion and uni life. 
Recommended for: getting opinions or answers from other students, sharing exam thoughts
Not recommended for: revision (due to tendency to procrastinate browsing random forum topics).