My last post was a test/demo of a bug I had encountered in the way FireGPG 0.5.2 was handling scooping up text from fields to clear sign and dump back. The signed text was in a very subtle way not exactly the same as the text in the field to start with.
Perhaps this was a problem on the order of a plaintext URL typed into the field vs. the URL with some underlying HTML being scooped up by the plugin.
In any case, the result was unreliable signatures. I've updated to 0.6.1, and the test blog entry below now validates correctly once the appropriate public keys are added to your ring.
The original authors and community forming around the plugin is doing a great job!