In addition to copyright, the other main concept that you should be aware of is trespass to chattels. Unlike traditional trespass, which refers to unauthorized use of real property (land or real estate), trespass to chattels prevents or impairs an owner's use of or access to personal property. The trespass-to-chattels laws were written before the invention of the Internet, but in certain instances, they still protect access to personal property. Consider the following examples of trespass to chattels:
Blocking access to someone's boat with a floating swim platform
Preventing the use of a fax machine by continually spamming it with nuisance or junk faxes
Erecting a building that blocks someone's ocean view
From your perspective as a webbot or spider developer, violation of trespass to chattels may include:
Consuming so much bandwidth from a target server that you affect the website's performance or other people's use of the website
Increasing network traffic on a website to the point that the owner is forced to add infrastructure to meet traffic needs
Sending excessive quantities of email as to diminish the utility of email or email servers
To better understand trespass to chattels, consider the spider developed by a company called Bidder's Edge, which cataloged auctions on eBay. This centralized spider collected information about auctions in an effort to aggregate the contents of several auction sites, including eBay, into one convenient website. In order to collect information on all eBay auctions, it downloaded as many as 100,000 pages a day.
To put the impact of Bidder's Edge spider into context, assume that a typical eBay web page is about 250KB in size. If the spider requested 100,000 pages a day, the spider would consume 25GB of eBay's bandwidth every day, or 775GB each month. In response to the increased web traffic, eBay was forced to add servers and upgrade its network.
With this amount of requests coming from Bidder's Edge spiders, it was easy for eBay to identify the source of the increased server load. Initially, eBay claimed that Bidder's Edge illegally used its copyrighted auctions. When that argument proved unsuccessful, eBay pursued a trespass-to-chattels case.[89] In this case, eBay successfully argued that the Bidder's Edge spider increased the load on its servers to the point that it interfered with the use of the site. eBay also claimed a loss due to the need to upgrade its servers to facilitate the increased network traffic caused by the Bidder's Edge spider. Bidder's Edge eventually settled with eBay out of court, but only after it was forced offline and agreed to change its business plan.
How do you avoid claims of trespass to chattels? You can start by not placing an undue load on a target server. If the information is available from a number of sources, you might target multiple servers instead of relying on a single source. If the information is only available from a single source, it is best to limit downloads to the absolute minimum number of pages to do the job. If that doesn't work, you should evaluate whether the risk of a lawsuit outweighs the opportunities created by your webbot. You should also ensure that your webbot or spider does not cause damage to a business or individual.
[89] You can find more information about this case at http://pub.bna.com/lw/21200.htm. Googling eBay, Inc. v. Bidder's Edge will also provide links to comments about the succession of rulings on this case.