• "I just wanted to take my time to thank you for all the hard work you have put into the site. It helps me a lot with biology. Keep up the good work!" - N.A., 9th grader, USA
• "I have recently started doing my A-Levels - I'm really enjoying it and your website has really helped me. P.S. I LOVE your dogs!" - N.W., United Kingdom
• "One of my favorite things was the puzzles. I had a blast with those and everyone knows that you learn a lot while having fun!! Thank you so much for providing such a great learning tool that is good for students of all types (and ages)!" - M.F., USA
• "I came across your "How big is a..." animation and just wanted to let you know that it's mad cool. Way to rock!" - McK.M., USA
• "I'm writing a book which is a directory of useful internet websites. The book is in Kurdish, which is the language of Northern Iraq, where the book is going to be published. I'm putting your website in the biology section." - I.H., Iraq