I bit the bullet today and moved from dasBlog to BlogEngine.NET after having upgraded my hosting account to .NET 4.0 and having way too many problems with my dasBlog install. I just exported the dasBlog content to BlogML.There are multiple posts about doing this.

The only thing I changed was the Global.asax code to create a permanent redirect for my dasBlog links out in the world to the BlogEngine.NET links using the following:

void Application_BeginRequest(object source, EventArgs e)
{
   HttpApplication app = (HttpApplication)source;
   HttpContext context = app.Context;
    
   // Attempt to perform first request initialization
   FirstRequestInitialization.Initialize(context);

   //redirect to ~/post/2012/03/30/DomainAspects+Inject.aspx
   //when url is ~/2012/03/30/DomainAspects+Inject.aspx
   if (context.Request.Url.AbsolutePath.EndsWith(".aspx"))
   {
      Match m = dateRegex.Match(context.Request.Url.AbsolutePath);
      if (m.Success)
      {
         string url = context.Request.Url.AbsolutePath;
         string dt = m.ToString();
         url = url.Replace(dt, @"/post" + dt);
         context.Response.RedirectPermanent(url, true);
      }
   }
}

static Regex dateRegex = new Regex(@"(?<!/post)/\d{4}/\d{1,2}/\d{1,2}/");