Spiders, go home!
Take a look at this ZDNet story that has some commentary on the recent Ebay-Bidder's Edge court decision. A judge granted an injunction to keep Bidder's Edge from using web spiders to grab information off Ebay's site, likening the practice to trespassing on Ebay's servers.
Of course, the implications of this are huge. The article points out that if the ruling is upheld, companies could conceivably forbid search engines to index their web sites. From there, it's only one step to a company demanding money from a search engine company for the "privilege" of indexing its site.
Fortunately, this isn't settled yet. A group of law professors has filed a brief urging the Court of Appeals to overturn the decision; hopefully the intervention of people who actually understand how the web works (and how this decision would completely destroy it) will prevail here.