Although the original poster did not state a reason for why they wanted to detect such a domain - others have since suggested that the web site content on such a "parked domain" is of no (original) value since only ads run on such a site. By that definition all billboards or stand alone advertising has no intrinsic content value. That complaint is justified only if you are lured into such a site under false pretense - such as by the site owner's active efforts at search engine pollution - so the "offending" behaviour has to go beyond simply running ads on a "parked domain" to which you may not have been solicited. Mistyping or typing in domain names and ending on such a site is a grey area - for example you dont blame the owner of a misdialed phone number for running any service they like on such a number just because it is two digits transposed from a "well known" or your otherwise intended phone number. That can go both ways - several cases of the wrong toll free number getting flooded with calls or the storied error from the 2004 US Presidential campaign when the Republicans sent the TV audience off to a Democratic leaning web site. Yes, there are some speculators that are counting on user errors of omission or commission but an algorithmic divining of what the intent is is problematic. Domain names are the "real estate" of the 21st century. You may wish to acquire a property for its "location", rent it to someone else now, and only wish to use it for your own use in the future. You could just leave it unoccupied. This would only be considered a problem if you engaged in deceptive advertizing outside that property to lure someone in and tried to sell them something else. That said, search engines do have their own heuristics on how to rank such pages "lower" in search results. Any articles that describe how Google's page ranking works talks about ratio of native content to hyperlinked content, number of outbound links to inbound links etc, number of links to other pages on the same site (many "parked domains" are single page sites but the reverse is not always true) Finally, if you have registered a domain lately - the web site associated with the domain is automatically associated with a "parked" page by most registrars (Network Solutions, Yahoo!, GoDaddy) immediately upon completion of registration and they run their own (revenue accruing to the registrar) ads on it till such time as you configure your own DNS servers and point it elsewhere. The maligned "middleman" comes into the picture later. I am as frustrated as the next person when I end up on a site that lured me in with clever manipulation of keywords and search engine optimization - only to show me ads - but I would be loath to paint all "parked domains" with a broad brush. Parked: A domain hosted by a middle-man for the sole purpose of generating revenue from pay-per-click advertising. Characterized by having no content of value.