Fiona Broome explains the meaning and origins of the phrase "Mandela Effect." (It came from a 2009 conversation at Dragon Con.)
This is a five-minute video explaining some unique qualities of alternate memories. In many ways, the Mandela Effect is very different, in contrast to other paranormal research. If you've wondered what the Mandela Effect is, this video is a good place to start.
Mandela Effect - What is it?