Define: Ranking Agent
Ranking Agent: Type of software application that makes multiple requests to different search engines in an attempt to see where a site lies within the returned results. Abusing these types of applications can result in penalties against the domains using them.
If your clients are using ranking agents, be sure to remind them to control application requests (to only once or twice per month). Also keep in mind there may be a huge number of requests at any given time by multiple domains using these applications. Ranking agents can put a real strain on search engine databases.