The device won't install apps directly off the developer's website - it will only install apps either through the actual app catalog, or through a free link that somehow goes through Palm. However they said that they would provide these links for any app, even without any formal review process. Really, this is a good thing.
Why? Because Palm needs to be able to yank an app if it turns out to be malicious. They are doing this to protect their platform, and it's a reasonable security measure.