Microsoft’s MSN Messenger, or Windows Live Messenger as it’s now known, will be fully retired on October 31st. The software maker originally announced its plans to shift users over to Skype last year, but Microsoft kept the service running in China. MSN Messenger started off life in 1999 as a rival to AOL’s AIM service. Both companies battled over chat dominance, and Microsoft engineers reverse-engineered AOLs chat protocol to allow MSN Messenger to sign into AIM, a process that AOL wasnt happy with when Microsoft first released its instant messaging client.