Domain name front running
Domain name front running is the practice whereby a domain name registrar uses insider information to register domains for the purpose of re-selling them or earning revenue via ads placed on the domain's landing page. By registering the domains, the registrar locks out other potential registrars from selling the domain to a customer. The registrar typically takes advantage of the five-day "domain tasting" trial period, where the domain can be locked without payment.
The term was coined by domain investor and retired stockbroker Daniel Stager. ICANN "likens this activity to front running in stock and commodities markets and calls this behavior domain name front running. ... There does not appear to be a strong set of standards and practices to conclude whether monitoring availability checks is an acceptable or unacceptable practice."