Yes, it is complicated. That said, this is partly just because there aren't enough cases - and partly because the law hasn't stabilised (took a century to stabilise after invention of printing press). It isn't clear what rights society should grant yet, for maximising business.

My take on it, from ScraperWiki's point of view: http://blog.scraperwiki.com/2012/04/02/is-scraping-legal/