I believe interactions via video and online communities can replace face to face communication. I believe this is particuarly true for video communication because it is essentially the same as face to face communication. I believe this is why it is used so much by professionals and family members that have distance between them.
While video and online communications are helpful in letting people communicate over long distances, it does not replace face to face communications. Through the internet you are not able to feel the presence of the other person, you can not touch them or interact with them physically. Face to face interaction can not be replaced.
No, interactions via video and online communities are wonderful for maintaining relationships that have already been established through face to face communications, but they fail as a stand-alone method for effectively interacting with others. Human beings thrive through human touch and contact and through interactions with others in the physical plane. A relationship, work-related or personal, will not continue to thrive with video and online communication alone over long periods of time.
In many situations, video communication and online communities can replace face to face communication. They can't completely replace the experience of interacting with somebody directly, though, there's a personal touch to actually being in front of somebody that no matter how advanced technology gets nothing is ever going to feel exactly the same as.
I do not believe that interactions via video and online communities can ever replace face to face communications, nor should they. People need actual physical contact with one another, which is something that the Internet can never provide. Eventually, people would get tired of doing things strictly through a monitor.