So what is the legality of this? Apart from the risk of having someone pull the plug on the way one takes the information out, when is something without a proper license able to be used?
1. the collection and assembly of pre-existing material, facts, or data;
2. the selection, coordination, or arrangement of those materials; and
3. the creation, by virtue of the particular selection, coordination, or arrangement of an original work of authorship.
However, if what you're scraping are not "facts", but some creative works, such as blog posts, product descriptions, etc, then it is likely to be copyright infringement.
Then on top of that, even if there is copyright infringement, other defenses such as a license to use the data, or fair use may apply.
I'm not so sure. It would definitely be illegal in the US for me to cherry pick data out of Google Maps and add it to OpenStreetMap (and OSM has policies addressing exactly this).
They scrape everything in the world they can get their hands on.
It's a sad state of affairs when i'm not even allowed to scrape data generated using taxpayers' money, like the (required by EU laws) noise maps for cities, which I'd like to use to augment real estate offers, for example.
I think it's only the UK that has copyrightable fact databases