I've had this question thrown at me a few times, "I want to blog and I want to podcast. Should I have a separate website for both?" I'm not sure I have an answer, but after thinking about this I went back to "It's all about the listener."
Here are my thoughts, if you're reading this please leave a comment (I'd love your opinion).
To me, people reading a blog are reading the content. If you then put in a podcast post with notes like "Show 16 with Steve Smith." That breaks up the flow of text.
However if you put show notes that read "Today I spoke with Steve Smith of the blah blah blah company and he gave us his insights into (topic) and how he had overcome some of the common problems that people find in this field (etc,etc, etc). Then I don't think it would "break the flow" of a blog. It would be a blog with a "play" button. I don't think you would interrupt the blog, and I think the blog (and extra text ) would serve as "Google food" and possibly grow your podcast audience. Especially if after your blog post you put "click here to listen to the interview."
My other question would be, "Are you trying to get blog readers to do one thing, and podcast listeners to do something different? Then you need two sites. It does make it easy as a podcaster to say "Go to ___.com for all of our show notes, contact information, and blog. Instead of "Go to ___.com for our show notes and ___.net for our show notes (This is something I've done with the School of Podcasting podcast. It's a nightmare, and I will be merging the podcast with the business website later this year). You want to give listeners A (as in single) call to action. Having too many choices may intimidate listeners and readers.
Those are my thoughts straight out of my head. I would love your comments. Is there one answer? Does it depend? If so on what?