Digg submits from WordPress are invalid?

It is not a WordPress specific problem. I can submit my sites to Digg without issues. No idea why yours in particular is failing.

The thread on the similar issue is here.

Is it perhaps the way that the permalinks have been formatted – e.g. they currently read https://www.fogofeternity.com/index.php/2008/05/lost-on-the-internet/, whereas your permalinks do not reference the php?

If so then I may just suck it up when it comes to fogofeternity.com, but can make alternative arrangements for cannon-on-sports.com. Thing is, when I choose ‘Custom Structure’ in the ‘Customize Permalink Structure’ in the dashboard, and remove the index.php section, both existing (if republished) and new articles return a “Page not found” when clicking on the permalink from the home page.

While I doubt that the index.php is causing your problem, the reason you need it is that you’re running on an IIS server. Use a Linux hosting solution instead, running Apache. Then you won’t have that problem.

I am having the same issue – it’s definitely WP related – I see many posts on the same problem. I do not have and have never had the Bad Behaviour plugin either.