After a bit more experimentation, it looks like I might need to hack around with WordPress MU a bit more than I originally thought. Which suggests that perhaps it’s not the best thing to use for the travel blog site.
Stuff that’s very important is the ability for users to upload photos into their blogs inline easily (and not by uploading first and then adding the uploaded photo to the post) and a fixed list of categories, to be used to associate posts with places. Apparently WordPress has “global categories” but there is no common list of categories. Instead, if a user creates a new category with the same name as someone else’s category, they will become associated. This probably stems from the fact that WordPress MU is based on WordPress proper, which doesn’t have any support for multiple blogs and this was the easiest way to provide such a feature.
Also, a big problem with WordPress MU is that it doesn’t work very well with Internet Explorer. The WordPress crew also seem to have some sort of vendetta against IE, putting a link to a web site encouraging you to switch browsers at the bottom of the admin page. It’s kind of arrogant really. They’re probably saying “don’t use IE because it’s bad*” because they don’t want to say “we’ve only made this work with Firefox et al”. There’s also no use complaining that IE doesn’t implement standards properly, because IE is by far the most used browser. You have to e pragmatic. (* The linked-to site talks about security problems with IE.)
So, I shall now head back to my feature requirements list and evaluate some other platforms as well. Drupal and ELGG seem to be in the running as well as WordPress MU.