However our wifi is not very well so I went offline and stored things in a text file instead. I added a beep to the scanner and merrily beeped away for a while. At the end of this I'd scanned over 300 books which I uploaded to LibraryThing. It thought about them for a bit, it cues batches so as not to overload Amazon with search requests, but after less than a day it had uploaded them all here. It even worked for maps.
A few books wouldn't scan easily and I found that lifting the scanner away once I'd run it across the barcode helped. In the end I think about 6 or so books wouldn't scan at all, something to do with the background colour on the back page I suspect. I had to manually added them to the list. A few books don't have barcodes but they do have ISBNs or equivalent and I typed these in too. I've got a few doubles because I added some books by looking at other peoples libraries as well but there's a tool that finds these so they're easy to sort out.
Still, it fairly rocks and I expect I'll do some more soon, even the pile in the attic. I also plan to add some more tags now that I've worked out that it can be done to groups of books with another online tool.
You can join for free but are limited to 200 books per year so I went the whole hog and paid $25 for a lifetime membership. I imagine this means theirs rather than mine, but you can easily download your file anyway. $45 for the tools to catalogue all my books seems pretty fair, and there's even a link for mobile phone database access.