This web 2.0 technology is great because it can be embedded in to most blogs or web pages. Voki.com will tell students how to embed this technology in to most forms of web resources. This means that students only need to be able to find the html code to insert a voki. Since the voki pulls information from Voki.com students only have to sign in at one location to make changes. This means that you could put the same voki in 5 or 6 web blogs or discussion boards.
http://teachweb2.wikispaces.com/Voki goes over some basic strengths and weaknesses of using a voki for learning. I agree with most of these except that teachers need to be cautious that the voice does not always pronounce words correctly.
Teachers should consider using something like a voki if they want a character to talk to the class. For example, Abraham Lincoln has a premade character and you could use it to talk about the civil war. Be careful each voki can only talk for 60 seconds or so.