Margaret Stewart 'user experience master' and one of the top designers at Facebook talked about designing to the scale of hundreds of millions of users. She talked about the amount of work that went into the LIKE button. They rely on empathy in design. Data analytics not as important as intuition. Change has to be managed carefully.
Her talk really deals with the use of symbols in the context of a complex communications ecology. "Know who you are designing for. "
Can you design for a low end cellphone?