Earlier, I was interested in how many pages google indexes over time, today, I’m interested in how many emails are sent. After two hours of research, I still haven’t found a reliable source. However, a paper by Jaeyeon Jung and Emil Sit gives me some indication at least. It seems that between 2000 and 2004, for one particular mail server, the number of accepted SMTP connection daily went from around 25k to 320k which suggests email traffic doubles every 13 months.
Anyone has more accurate figures?