Reading Adam Kalsey's post, Six Apart Musings (where he posts his "thoughts on the future of Movable Type, Six Apart, and [his] plugins"), I was struck by comments from Jonathan Sanderson.
Hypothesise a new competitor product, akin to WordPress but with (say) gallery/moblog features integrated fairly well. If it sold for $40, how many customers would Six Apart lose? $50? $30? GPL? Define the product that worries you most, and you've found your middle ground.
Hey -- that's us! Both the gallery and moblog features are just OK right now, but we'll be doing some work on that plus playing with Flickr integration as well.
(BTW, I found this post via Matthew Mullenweg, one of the WordPress lead developers. WP is a great individual blogging tool that just happens to be open source as well. Is there a company offering hosted-WordPress we can point people to?)