"At blogging, iWeb is weaker than any other solution I've seen yet, including the previously-included-with-.Mac iBlog. Nothing is auto-formatted, and every entry has to be adjusted by hand to remove/resize the entry's image, text location, colors, etc. The built-in templates are pretty weak and hard to customize. There is no integrated commenting or haloscan support."I too just played with iWeb at the Apple Store.
Two things stand out.
One, when you publish a movie from iMovie HD, iWeb seems to take the first frame of your movie as the image. In the case of the movie I used from the Apple Store, the first frame was black, so the movie image on the blog was black.
Two, when you click publish, iWeb reposts everything. it should really just post your changes. Or at least, just post your new entry.
I'll give the developers a change to add features and revisit iweb int eh future.