Screenshot of taken Monday, November 25, 2014.

While preparing to announce the results of a grand jury investigation into the death of 18-year-old Michael Brown, the city of Ferguson did more than just build barricades and increase the number of cops on the street. The city of 21,000 upped its security on the Internet, too.

Some visitors to the city's Web site  Tuesday -- which also hosts a page for the Ferguson police department -- were greeted with a note saying "Checking your browser before accessing" that briefly delays their access to the city Web site.

The check is aimed at warding off what's known as distributed denial-of-service attacks designed to bring down a Web site. Such attacks, known as DDoS, overwhelm a Web site with traffic, making it more difficult to reach.

Richard Stallman, a software freedom activist, has likened such attacks to a digital embodiment of the sort of street protests seen in Ferguson. "The internet cannot function if websites are frequently blocked by crowds," Stallman recently wrote, "just as a city cannot function if its streets are constantly full [of] protesters."

The city uses security software from San Francisco-based CloudFlare. The security setting currently being used by Ferguson's Web site is known as "I'm Under Attack," said Matthew Prince, CloudFlare's chief executive. The service works by forcing users' Web browsers to solve a math problem while they're attempting to access the relevant Web site. The complexity of the math problem is based on the users' online "reputation," determined by what kind of device is being used to access the site, the location of the user, their past behavior, and the likelihood of them having a legitimate reason for visiting the site in question. The goal of the puzzle, says Prince, is to add enough "friction" to the process that those interested in sending enormous amounts of traffic to a Web site will give up.

Such online denial-of-service attacks are a favorite tactic of the hacker collective Anonymous, which (unsuccessfully) attempted to unmask the police officer involved in the shooting death of Michael Brown. In the past, Anonymous has attacked the online properties of MasterCard, Amazon, and the Church of Scientology to punish them for various misdeeds. In those cases, access to those sites was slowed significantly.

It's unclear exactly when Ferguson added the DDoS protection to its Web site. A call to the city's Web site vendor was not returned and the city of Ferguson's general voicemail box was full.

But the added security is a sign of a town (or, likely, its digital consultants) recognizing that in 2014, being in the news makes it vulnerable online as well as off.