Complex sentence: SmarterChild was a chatterbot available on the AOL Instant Messenger and Windows Live Messenger (previously MSN Messenger) networks that became popular in the early part of the 21st century, with continued user popularity until its demise in May 2009.
Split into simpler sentences: SmarterChild was a chatterbot available on AOL Instant Messenger and Windows Live Messenger (previously MSN Messenger) networks. SmarterChild became popular in the early part of the 21st century, with continued user popularity until its demise in May 2009.