It links to most popular web photohosting sites and imports your images ready for use, and uses a Flash UI to lay out your presentation pages, with custom photo frames and text - just like a scrapbook or a photo album. You can resize and rotate images. You can add extra pages to Scrapblogs as you go, so you're not limited by a single page - and of course published pages aren't locked down, so you can update and edit them any time you want.
The UI is impressive - it's currently built in Flex, so does a lot more than your average Flash application. There's an Apollo port out there too, so you won't be limited to working through web pages.
I wouldn't see this as a replacement for Flickr or any other site like that - this is more a way of quickly selecting a group of images, and then sharing them with friends and family who wouldn't normally spend time delving through a Flickr photostream...
Here's my Scrapblog
My one quibble: for some reason the application defaults to US keyboard settings