"With WeVideo, you simply upload your video clips and photos, create your storylines, and edit them in the cloud. Oh, that "cloud thing", it means the delivery of computing as a service rather than a product. For you that means there's no software to download. All video story creation takes place in the browser on your smartphone, tablet, or computer."
Prezi started in a very organic way; Adam and Peter - an internationally recognized emerging designer and a highly skilled computer scientist - have been lecturing extensively. Due to the limitations of slide presentations they developed their own method by using scripted maps, to hold these lectures. Over time (last 4 years) their methods matured, got refined.