DomainTools isn't as popular as it's Alexa rank would imply but it does get a lot of visits and they manage to get many of their visits by scraping only the most important SEO related content from the over 100 million registered domain names without giving anything back to the sites they're scraping from. At one point they even had a close relationship with Google.
Let's look at what's really going on.
Unreliability of Alexa RankWhile Alexa Ranks are pretty useful they are based on educated guesses. Part of the information Alexa uses to determine a site's rank comes from users that choose to use Alexa's toolbar or related plugins.
Since Alexa Rank is pretty important to people who build and maintain websites, and this group would also have a legitimate reason to want to visit DomainTools.com it's reasonable that their Alexa Rank would be higher than normal.
Looking at other sites like Compete.com shows that DomainTools is ranked at 946 and they receive almost 2 million unique visitors. This data is also an estimate. For reference, Compete.com indicates PNC.com is ranked at 264 with about 5.6 million unique visitors. Alexa ranks DomainTools.com and PNC.com pretty close.
Whatever the exact numbers are DomainTools is getting a lot of traffic even compared to other sites that serve a similar purpose.
Google and DomainTools Relationship
At one point if you did a Google search for "whois domainname.com" above all the other search results there would be a link to that domain's page on domaintools.com. Similar to when you do a definition search on Google.
That relationship ended some time ago. I wouldn't argue that having that type of listing was bad. Whether Google had some sort of business relationship with DomainTools or if they just felt it was a useful site for visitors that searched for whois domainanme.com, DomainTools would be a useful site for that searcher.
However, DomainTools.com is coming up with high SERP rankings for searches that don't include the whois term in the search results. According to Alexa.com a lot of the traffic going to DomainTools is coming from searches for facebook.com and www.facebook.com.
.com has become associated with many online sites even if they're not branding themselves as brandname.com. When someone does a Google Search for facebook.com do you honestly think that most of those people are looking for information related to the domain name? Google Seems to think so. In fact they seem to think it's more important than some other items like Facebook's Twitter page.
DomainTools is not the only site that comes up in these searches but it is the most prevalent one. Hey Google, just because I put ".com" in my search doesn't mean I want to see thousands of links to sites that scrape content from whois servers or regurgitate Alexa Rankings in one way or another.
I know that Google sometimes personalizes results based on what they think they know about the user but I've done these searches on other computers of people that are not involved with web development and I saw similar results. It was just easier to grab the screenshot on one of my own computers.
Scraping SEO Content
There are a lot of optimizations that web developers use to make it easier for search engine crawlers to understand and classify their pages. This includes the domain name, title of the homepage, meta keywords and descriptions. Considerable thought, time and money is invested in getting the most out of these features.
DomainTools copies this content and uses that information on it's own pages to help their own pages rank well in search engines.
Just have a look at the image to the right and you'll see they use the site's domain name in their URL and as the H1 header tag for the page. They even use the site's domain name and title in their own page title.
Further down the page they list among other things the meta description and keywords they grabbed from the site. An interesting thing to note, they don't even link the header to the site they're scraping content from. More on that later.
Scraped Directory Content
Certain directories such as Yahoo's Directory and The Open Directory Project are also important aspects to a site's SEO as are references to the site on Wikipedia. DomainTools copies those pages onto it's own site.
To be fair, those directories allow their content to be copied so it's not like DomainTools is violating copyright when they do so but just look at this example for Netflix.com
The most obvious thing is that it's not even a copy of the Wikipedia Page on Netflix. It seems that they just pull any reference from Wikipedia including items on Talk pages. If you click on the big link at the top for "Netflix.com" you won't go to the Wikipedia page for Netflix.com, where a reasonable person would expect to go, you'll just land back on the page you're on.
When they do link to content on the actual Wikipedia site, they do so using a rel=nofollow attribute in the anchor tag. So even though they think Wikipedia is an important enough site to copy content from, it's not important enough that DomainTools thinks they should let search engines know they feel that way.
No Links? No Follow? Are You Kidding!?!?!
Wikipedia isn't the only site DomainTools doesn't think deserves to have PageRank passed to it. The very site the page is about isn't good enough!
Not only is it not good enough to pass PageRank it's not even important enough to provide a direct link to! You don't even find a link for Netflix.com until you click on the Site Info tab.
That's right. When you first land on a whois page on DomainTools.com you won't even be able to click on a link for the site the page is about. Well, unless of course that site happens to advertise through Google AdWords or Chitika. In which case the site winds up paying for the privilege of having their content scraped.
In the case of Netflix, ads for their competitors showed up on the top of the page.
AboutUs.org Is Worthy Of PageRank?
DomainTools.com isn't completely stingy with their PageRank. They have no problem linking to AboutUs.org, which is another generally useless scraper site that Google chose to rank highly in the past.
The link to the Netflix page on AboutUs.org not only is a do follow link, they even disguise the link in a way that some users may think they're clicking on a link for Wikipedia. (Many people use the general wiki term as a reference to Wikipedia.) They even go so far as to use the title attribute "Visit the site" which may confuse people into thinking they're visiting the site that page is about, in this case Netflix.com.
What Happened To Build Pages For Humans Not Search Engines?
This is what Google and Matt Cutts tell those of us building websites to do. If we don't we can be penalized by having our pages rank lower, or even outright removed from Google Search Results.
Here is a case of a site that clearly is focusing their efforts on search engines and not humans and not only did Google chose to not penalize them for it, they actually help promote them.
I'm not saying that DomainTools, or sites that consolidate information from various other sources in general, do not provide value for visitors. They absolutely provide value. They just provide value to a small subset of users but Google is jamming site's like these down our throats.
On top of that DomainTools, and other sites, aren't being good Netizens. A term that isn't being used as much these days. They take data which others have worked hard to create and use it for their own benefit, without even doing something as minor and easy as passing along some PageRank or even making it easy for a visitor to view the page being referenced if somehow they were looking for that page and not geek SEO babble about the page.
C'mon Google. I thought you were starting to care more about the billions of people that use your search every day.