Finally we have an add-in/extensibility model for Expression Web that does not require you to create a com application or use Visual Studio. The new extensibility model uses html, css, javascript and an XML manifest (and there is even an add-in to create the manifest!)
As a result we are already seeing more add-ins in the Expression Gallery for version 4 than all other versions combined. Get them at:
http://gallery.expression.microsoft.com/en-us If you want to create your own here are some resources for you:
Gallery search for Expression Web results:
