Well, it turns out that like Bing and Google, Majestic-12 is actually a bot. I have googled the internet to find out a little bit more about this bot. Here is a site associated with this "user."
Here is an Introduction from that web site:
I would suggest that you all say hello to Majestic-12, but I am not sure it makes sense to do so to a bot.Majestic is a UK based specialist search engine used by hundreds of thousands of businesses in 13 languages and over 60 countries to paint a map of the Internet independent of the consumer based search engines. Majestic also powers other legitimate technologies that help to understand the continually changing fabric of the web.
Web site owners can see data about their own websites on majestic.com.
MJ12Bot does not currently cache web content or personal data. Instead it maps the link relationships between websites to build a search engine. This data is available to technologies and the public, either by searching for a keyword or a website at Majestic. Details about the community project behind the crawlers are at Majestic12.co.uk.
What is MJ12bot doing on my site(s)?
We spider the Web for the purpose of building a search engine with a fast and efficient downloadable distributed crawler that enables people with broadband connections to help contribute to, what we hope, will become the biggest search engine in the world. Production of a full text search engine at Majestic-12 is currently in the research phase, funded in part by the commercialisation of research at Majestic.
I presume W.J. Fox has no problem with their bot's duly registered use of this site, but I will leave it to him to comment further or take other actions as he may deem appropriate, including simply ignoring this introduction.