Time to update that list:
FACEBOOK makes you sharper but Twitter makes you thicker, a psychologist has said.
The social networking site boosts a part of intelligence that is vital to success in life, while tweeting away may have the opposite effect.
Keeping up to date with Facebook may have the same effect as playing video war games and solving Sudoku, said Dr Tracy Alloway of Scotland's University of Stirling.
It hones the ability to remember information and to use it, known as "working memory".
At a job interview, a candidate will use working memory to match answers to questions in the best way.
Dr Alloway has studied working memory and believes it to be far more important to success and happiness than IQ. […]
Sudoku also stretched the working memory, as did keeping up with friends on Facebook, she said.
But text messaging, micro-blogging on Twitter and watching YouTube were likely to weaken "working memory".
"On Twitter you receive an endless stream of information, but it's also very succinct," Dr Alloway said.
"You don't have to process that information. Your attention span is being reduced and you're not engaging your brain and improving nerve connections."