Chat
You can create a single chat, without channels (5.3.2. Channels) this is useful for 'one-way' communication from a user with dedicated person on the receiving end (think of a support chat).
This can be achieved by creating a ChatContext-object and providing it to the page as desired (datasource or parameter), configuring the ChatContext_ChatMember_Current association as desired and placing the snippet SNIP_Chat on your page with the ChatContext parameter available.