Spout spanks Flypaper and GoldMail.
Sprout is a Flash authoring environment that puts the two Flash authoring environments I just covered to shame. Completely Flash based, it lets you put all your media into a Flash app that's easily pushed into widgets.
Spout widgets also let viewers subscribe to updates to a presentation via RSS, share them, and so on.
In the demo the CEO showed Spout's clear and capable authoring environment. Unfortunately I can't show you the authoring environment because it's not yet live on the site. There's a video of the authoring environment here. And here's a widget created with it: