No error messages at all, it's just like trying to download a web page using an old 14.4k modem.  But since yesterday eveything now seems back to normal, including the marketplace.  All the graphics load almost instantly (as they should) as opposed to one graphic element, slowly, at a time.

One thing that I forgot to try (which I will the next time this happens) is to do a "ping test" and see if I can figure out where it's getting slowed down.