Quite good but for those not used to Mercurial I hear the words of Linus "branching is easy, merging is hard" about svn so the article really need a second chapter of howto merge those Anonymously Branches.
A guide to merging is an interesting idea, but it wouldn't necessarily be similar to this guide. This guide was about the different branching workflows/models in Mercurial, but there's only one merging model.
It could be useful to diagram out the concepts used in that single model though, so it's something I'll keep in mind for a rainy day when I have some free time.
Thanks for putting in the time to help others. Keep up the good work.