To join an email list before 1986, users had to wait for someone to painstakingly adjust the code to include them. For Eric Thomas, that was too uncomputerized for a computerized system. So he created Listserv, the first automated email-list-management software. It's still used to send group emails, though a lot more of them -- 30 million emails are sent using Listserv each day, a huge leap from 25 years ago, when electronic mail was just taking off.
Infographic: 25th Anniversary of Listserv 
Worldwide email accounts
1989 | 1.8 million
1996 | 100 million
2010 | 3 billion
In 2010, email use by...
Seniors + 28% & -59% Teens
The average businessperson sends 33 emails each day.
89% of all sent emails are spam, the majority of which are pharmaceutical promotions.
In 1985, 90% of all emails were business related. Today, just 8% are business related.
90% | 1985
8% | 2011
In 2010, there were...
107 trillion emails sent
170 billion pieces of mail sent
36 billion photos shared on Facebook
25 billion tweets posted
Users
Facebook
2004 | 1 million
2010 | 600 million
AOL
2004 | 23 million
2010 | 4 million