I have put an example of a video chat into the left sidebar of this blog Blogging Ideas. It is near the bottom of the first left sidebar, just above the clock. You can leave a message by clicking on "Click here to leave a video message" and if you have a microphone and a webcam on your camera (I have both) and I happened to be online and signed in, we will be able to have a live video chat. However, don't expect too much from me because I am not really interested in having video chat and that has been put there for demonstration only.
I haven't really tested WengoVisio, but I think if you leave a video message when I am not signed in, I will probably receive an email notification of the video message with a link to the message which I would be able to view at time I chose. I just received such a email notification and had thought of posting the link to that message, but had second thoughts as it may be an invasion of privacy.