The BuddyPress @Mentions is it’s system for sending site members a public message, similar to writing on a users wall in Facebook since the mention will turn up in that users activity stream. @Mentions is normally a one to one thing, if you want to have more than one person in your mention then you must include @member1, @member2 etc. In your activity update.
BP Portfolio is a plugin designed to allow artists to showcase their images on a BuddyPress Site, the free version supports photo’s whilst the Pro version adds support for video and Audio files. BP Portfolio adds a new page to BuddyPress called projects through which artists are able to showcase their works.