Digg
After some fiddling, I’ve managed to work out how to put a "Digg This" button on this Blogsome blog.
You will see the button at the bottom of this post. There are some WordPress plugins to accomplish this, in quite a sophisticated way, but these aren’t available for Blogsome blogs.
The Digg Tools page has instructions on how to ‘integrate digg in your site’ (I also got the button graphic from here), but they are very general. After some experimentation, I found that if I use the following hyperlink, based on their instructions, it seems to work:
http://digg.com/submit?phase=2&url={permalink_link}&title={the_title}&bodytext={the_title}&topic=linux_unix
There are some minor things I still need to work out. I use the title for the "bodytext"; what I really want to do is use the "Excerpt" that appears on the RSS feed. I’ve also hard-coded it to use the "linux_unix" topic, which won’t be quite suitable for all my posts. I think I may be able to get round this by using "Custom Field" feature when making a Blogsome post.
They talked about having to "URL encode" the permalink and title. I didn’t do anything to do that, but it just seems to work.
Hope you find this useful. You could always "Digg this story" if you do 
Copyright (c) 2006-2007 Michael J Kaye.
Permission is granted to copy, distribute and/or modify the content of this blog post under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.