Wesley Chan (@weschan) was Sergey Brin's Chief of Staff for 5-years in 2002. Here he tells the story of how in 2002 Sergey Brin and the team came up with Gmail. It was released privately, and invite codes were sold on eBay for up to $1,000 in the days after, just to use Gmail: "I still remember when the team was pitching him the original idea... the offer is going to be 250 megabytes. That was the original offer. 10x of what everybody else was doing 'cause Hotmail and Yahoo Mail both gave…