Paused positions are positions that remain technically "Open," but you have temporarily placed into a holding pattern. As such, Paused positions will no longer appear on your Careers page, or on the job boards the hiring system feeds to. The main benefit for Pausing a position is to get caught up on applicant processing (if you've received a large influx of applicants in a short time, or have many remaining New applicants to Review), or for when you are close to making a hiring decision on an existing candidate and do not wish to receive more new applicants who may not be necessary.
To pause a live position, you must first go to the My Positions tab. Then click the box to the left of the position you wish to pause. Click the Take Action button and select Pause.
Keep in mind, you can take a group action and pause several positions at once by checking all the positions you would like to pause and clicking the Take Action button and selecting pause from the drop-down. Likewise, you can just as easily "Un-Pause" a position when you are ready and it will automatically return to the Posted status, so you can continue actively recruiting.