It downloads it ALL (including pics from photobucket for example), just everything. Make sure you have quite a bit of free space on your hd, I was always surprised about the amount of data.
What you get is a folder, with everything in it, just double-click the index.html to open it in your browser and browse away (at very high speed, since it's all from the hd now).
Used it to download boards to read on planes.
That tool Rulez! I downloaded a copy of the board: 700Mib.
I'm not sure how we could use it to recreate the board if proboards failed. But that's OK. It's a backup, with all the info, and if proboards lost our board, hopefully they'd be open to recreating it based on my backup. And if proboards the company failed, hopefully we could find a tool of some other company that would let us automatically import the board.
At least I can sleep easy knowing that all the info is stored. I'll make a backup once a month.
Just as a final test, disconnect your internet connection and try to open your backup again, then click on reload while holding down SHIFT, this will make sure you're not seeing any cached version and it's making sure all the pics etc are indeed coming from the hd not online.
Reason I mention this, yesterday I started downloading the board but my connection is not the fastest and I needed the line free so I cancelled it. When I opened the index.html from the folder I saw everything was there but for example some of the profile pics were still linked to the web.
I'm pretty sure this was due to me cancelling the process but just to make sure...