In an e-mail message to Mr. Sesto, Rackspace’s senior corporate counsel, Beth Sherfy, said the company would not be the site’s host because it “could create a risk to the health and safety of law enforcement officers.” RateMyCop then found a third domain host, which Mr. Sesto would not identify, and is back online.

Six months ago, Mr. Sesto and the site’s other founder, Rebecca Costell, began sending letters to thousands of police and sheriff’s departments around the country requesting the names and badge numbers of officers. Based on the responses and information on department Web sites, they created a database of officers from more than 500 departments in every state except Maine, Rhode Island and Alabama. The site focuses on departments in major cities, including Los Angeles, San Francisco, Dallas, Atlanta and Miami.

Sgt. James Russo of the New York Police Department’s freedom of information law unit said the department would decide by the end of the month whether to send the Web site the requested information on its officers. Washington, D.C., and Chicago have turned down RateMyCop’s request.

Users can search for officers by name, department or state and give them up to five stars based on professionalism, fairness and overall satisfaction during an encounter.

Users must register with the site by leaving their names and e-mail addresses before rating or commenting on officers and are urged to flag inappropriate postings. Some comments have been removed after users complained that they were worrisome or offensive, according to Mr. Sesto. “We want a safe environment,” he said.

Mr. Sesto said he had decided to create the site after trading stories about traffic tickets with a friend last year. “There are sites like rate my doctor, rate my lawyer, rate my teacher, so why not have rate my cop?” he said. “We are taxpayers. We pay for the service that’s provided, so why can’t we give feedback on that service?”

The average rating since Feb. 28, the site’s first day online, has been 3.7 stars.

Many users gave high marks and thanked officers for being helpful or professional. Among raters who were not as impressed was “imdlaw1” who gave two stars to a San Diego sheriff’s deputy and described him as “a little red-head napoleon.” “Tate” described his encounter with a Dallas police officer with one word: “Lies.”