Which API should I use for a web app?

[ryan]

I'm looking at the slide client library, the slide API, and the WVCM
API, and I can't figure out which one I should use for a web
application.  Can someone explain what the difference in these API's is?
 
Does the Slide API support versioning?  Would the Slide API be much
faster than the other two because of the network traffic?  Which API
will support external transactions in the future?
 
Thanks,
 
Ryan Rhodes