Sony released a video trailer about "Chat & Play" feature in a party but the teaser also showed "Friend Login Notification" for few seconds on the screen. The PlayStation community is expecting the feature from a long time and it looks like its finally coming.
Description for the above video(youtube)
"Hook up with friends to play together - or just to chat, no matter what games you're all playing - by setting up a Party on you PS4. This is for the players."
If you still can't see or just don't wanna see the video, here is a screenshot for ya