How long did you wait? Sometimes these things aren't instant as the 2 clients run from different servers so things like adding tracks etc might take a while to replicate through the servers. You could try to force a push by logging out of the desktop app and then logging back in again.
Please use the search feature before posting a problem/bug/idea. What's a Spotify Rock Star, and how do I become one? Using Spotify Since March 10th 2009 Twitter: @mechanimal82