Memrise is really an implementation of the Heisig et al approach to memorizing Chinese characters - imagine their components to be images/shapes of things which they mean, and use those mnemonic images to recall the characters' meanings. Which is, unsurprisingly, the original basis of most Chinese characters anyway, although they've undergone a lot of evolution in the intervening millennia.

Unfortunately I'm past the stage that I need to use mnemonics to remember characters, but it's certainly a useful tool for those starting out or at intermediate levels.