You know that Outlook.com is mostly an email service that also supports conversations. You can click on the chat icon on the web page to display the available contacts and the options for starting a video or audio call.
If you check the web site at this time, you should see the options to connect with friends on Facebook friends and your contacts on Google services as the site still allows contact with those contacts.
Η Microsoft but recently announced in a message email that it will discontinue support for Facebook Chat and Google Chat through its service Outlook.com.
E-mail appears to have been sent only to Outlook.com users using either Facebook Chat or Google Chat via Outlook.com. The reason for removing Google Chat is to withdraw Google Talk from Google trying to establish the Hangouts service.
Hangouts, unlike Google Talk, does not uses the XMPP protocol, and Microsoft notes that this change will affect chats but not Google or Facebook contacts added to Outlook.com or anyone else account of Microsoft.
The company recommends using Skype on Outlook.com, saying it "provides a better user experience for video and audio calls," according to ZDNet.
The change should be seen from the next few weeks to be applied to all users of Outlook.com.
Microsoft's decision probably wants to affect some Outlook.com users, to switch to its own service to chat with their selected contacts.