Seeking to broaden its appeal to younger women, Time Inc. has snapped up Hello Giggles Inc., operator of the pop-culture, beauty and lifestyle website HelloGiggles.com. It is the latest in a series of digital acquisitions aimed at bolstering the reach of Time Inc.’s most important magazine brands.

Terms weren’t disclosed. One person familiar with the purchase suggested it was in the range of $20 million.

HelloGiggles.com...