5 Biggest Email Service and Account Providers

3. AOL Inc.

AOL Inc. is a New York-based American web portal and online service provider. AOL Mail is a free web-based email service provided by AOL. AOL introduced NetMail in 1997, a web-based version of its email service. It was criticized for only supporting Internet Explorer. However, a later Java-written version secured Netscape Navigator compatibility. AOL mail offers POP3, SMTP, and IMAP protocols for electronic mail transmission.