This is part of a biweekly series on tools, resources and apps to help PR and media professionals be more productive and effective.

Concentrate is a Google Chrome browser extension that enables users to block distracting sites for a set amount of time. This simple tool, which bills itself as "vitamin C for your productivity," helps you to keep focused on whatever task is at hand.

Once you install the Chrome extension, you can click on the icon of a sliced orange in the upper right-hand corner of the browser. The drop-down panel displays two sections:

- Timer: Set how long (hours and minutes) you'd like specific websites to be blocked.

- Blocklist: Add the URLs of the sites you'd like to block.

After you've set the length of time and input all the websites you'd like to block while you're being productive, press the button to the right of the Timer section. This will cause a warning to appear: "Are you sure you want to start the timer? Once it is started, you cannot view sites on the blocklist until the timer finishes counting." You can choose to cancel the request or start the timer.

If you try accessing a site in the blocklist while the timer is active, you'll see this message:

To see how much time is left in the second-by-second countdown, just click on the sliced-orange button. URLs can be added and removed from the blocklist anytime the timer isn't running.

Concentrate is a straightforward productivity helper that's easy to install and use. It's especially useful for media and PR professionals who are self-employed, work with a personal computer or work in offices that don't filter distracting sites for them.

The key ingredient is, of course, an earnest pursuit of productivity, which only the user can control. Until there's an app or tool for that, Concentrate is about as good as it gets.

Another tool for reporters is ProfNet, a service of PR Newswire, has helped journalists and experts connect since 1992. Writers can search the ProfNet Connect database of more than 50,000 profiles; send a ProfNet query by email to thousands of subscribers around the globe; or get timely experts and story ideas by email.