Instinet Corporation, Overnight Transportation Company, Network365, and CIGNA all prohibit other sites from linking to them without specific permission. Instinet prohibits deep links entirely, and requires sites that have obtained permission to link to its home page to use a "jump page" containing an explanation of how links work and a disclaimer of liability, rather than linking directly to Instinet's site. Overnight's complex "Linking/License Agreement" enables sites to seek permission to link to Overnite's home page on a non-exclusive, revocable, non-assignable, non-transferable basis. Network365 prohibits "hypertext or other" (?) links without its consent. CIGNA requires sites wanting to link to its web site to download and print two PDF documents -- a Linking License Agreement and a Linking License Application Form -- then fill them out and fax them back to CIGNA, which promises to respond with its decision by e-mail within 10 business days.  DES permalink

Don't Link to Us! was featured today on CNET News.com, CNET Radio, Slashdot, and perhaps elsewhere. Thus far the site hasn't crashed, but I have set up some mirrors just in case -- the backup URL is www.dontlinktous.com. (By the way, only the most recent additions appear on the main page of this site; go to ARCHIVE if you want to see older links.)  DES permalink

Sonic Foundry requires permission for all links to its web sites (including ACIDplanet.com), and prohibits deep links to pages within those sites. MODEWeekly.com also requires permission for all links to its web site, prohibits deep links, and requires that all links use capital letters for the first four letters of its domain name and lower case for the remaining characters. Nikon Precision Inc. requires express written permission for all links to its web site, reserves the right to revoke that permission at any time, and insists that failure to remove unwanted links to its site will cause "immediate and irreparable injury." Finally, a few more sites that prohibit deep links: Big Brother/South Africa, and the Chicago-Kent Journal of Intellectual Property, and Dynegy Inc.  DES permalink

The International Trademark Association (INTA) requires that linking sites notify INTA of their interest in linking to its web site, and imposes a long list of restrictions on linking sites. For example: linking sites may not include (anywhere on the site or "within any context," whatever that means) any links to materials that might be interpreted as libelous, or that advocate the violation of any third party rights.  DES permalink

Here are some references for those wanting to read more about linking issues: Stefan Bechtold's The Link Controversy Page; Chilling Effects: Linking; SearchEngineWatch.com: Search Engines and Legal Issues; American Library Association: Deep Linking.  DES permalink

The American Cancer Society permits "approved" web sites to link to its home page, and reserves the right to revoke that permission at any time. The society's link request form requires the operator of the linking site to provide his or her e-mail address, physical address, telephone number, and other information, including the reason for linking to the ACS's site. Harcourt School Publishers and Trapware Corporation also require other sites to request permission before linking to them.  DES permalink

Law.com seems to say that no one may link to its web site at all. (Leave it to the lawyers at Law.com to draft a linking policy that is both extremely confusing and utterly clueless!)  DES permalink

The City of Colorado Springs requires other sites to ask permission before linking to its site, and reserves the right to rescind permission at any time.  DES permalink

ThinkQuest says individuals can freely link to its site for noncommercial purposes, but educational sites must notify ThinkQuest before linking, and permission is required for commercial links.  DES permalink

Universities UK prohibits deep links to its web site without prior written permission, and claims it has the right to have links removed upon request. Yet another site that prohibits deep links is Internet Management Solutions (New Zealand). Ditto for Gay Wired -- which actually demands that other sites notify it before linking to its home page.
Update (Aug. 28): Universities UK has just changed its linking policy to something much more reasonable. Other sites would do well to follow this example.  DES permalink

Texas Instruments says you can't link to its web site from a site with "content that could be construed as distasteful, offensive or controversial."  DES permalink

Note: This site exceeded its bandwidth allocation, and so I'm in the process of moving it to a new hosting service. Hopefully it will be back online at www.dontlink.com by tomorrow. (I don't recommend linking to the temporary version at www.but4.com/linking, since it will disappear once the site is back up at dontlink.com.)
Update (Aug. 15): I think dontlink.com is now back online. Thanks for your patience!  DES permalink

Andrew Corporation prohibits links to its web site without prior written permission, obtainable by completing the "Andrew Corporation Link Request Form." (I would have included a link to the request form here, just to make fun of it, but as far as I can tell it doesn't even exist -- at least not according to Andrew Corporation's site map and search engine.)  DES permalink

Huntingdon Life Sciences forbids linking to its web site without express written permission. (Huntingdon appears to be a British firm that opposes animal rights activists, perhaps because they were linking to Huntingdon's web site without permission.)  DES permalink

Shell (the oil company) says you may not link to its web site without Shell's express written consent. (Does Shell also prohibit people from entering the number 710.77345 on a calculator?)  DES permalink