I have two blogs by two users on the same DNN page.  The permalinks to the blog posts for one are "http://mydomain.com/.../post-title.aspx".  The links to the blog posts for the other one are "http://www.mydomain.com/.../post-title.aspx".  Anyone have an idea of why this difference (one has the "www" and one doesn't)?  Everything still works, but this inconsistency is unpleasant and since I have just upgraded the blog module to the latest, who knows what else will end up happening..

Yes on one of them.  I clicked on "regenerate permalinks" for the one that is producing "http://domain.com" type links.  I did not do so on the one that is producing "http://www.domain.com" type links.  

So if I do that on both, would both start producing "http://domain.com" type links?  

I would have preferred to have "http://www.domain.com" type links on both as that is really what my domain is: "www.domain.com".  I am actually afraid of clicking on "regenerate permalinks" again as I don't want to lose the "www".

 Thanks.  That doesn't answer the question:  what exactly caused the difference and how can I be sure that it won't happen again?