BizTalk Server vs Windows Workflow Foundation

When I talk to BizTalk developers about the new Windows Workflow Foundation I always have to explain the difference between BTS and WWF. There are a couple of good blog posts discussing the differences:

• BizTalk Server 2004/2006 and Windows Workflow Foundation, Brian Loesgen
• Windows Workflow Foundation vs BizTalk Server, Lamont Harrington

But Stephen Kaufman nails it in his latest post: "So, to summarize, Windows Workflow is great for workflow within an application whereas BizTalk is great for workflow across applications and this is precisely why BizTalk shines in Enterprise Application Integration scenarios."