If your business is targeting mothers online, you'd better have a social media marketing plan. At this point, it’s practically unheard of for moms not to use social media. But you need to be spot-on with your content, experts say.

According to a study sponsored by BabyCenter, an online parenting resource, more than 90 percent of U.S. mom Internet users said they use social media on a regular basis, market research firm eMarketer reported. Moms ages 18 to 34 spend 260 percent more time on social sites than the average user does.

The biggest difference between moms and the general population is their use of YouTube, the study found. Seventy-seven percent of moms used YouTube, compared with 61 percent of the general population. The difference in Instagram use was also significant: 27 percent of moms used the photo-sharing app, compared with only 15 percent of the general population. The smallest divide was on Google+ usage.

The research also found that moms have very specific content interests. According to the study, the top reasons for which moms reported using social media included connecting with other moms and friends and family, discovering information, and sharing family milestones. 

Ninety-two percent of moms who reported using social media said they shared family milestones on Facebook. Getting advice was also an extremely popular reason for moms’ use of social media.

eMarketer estimates that this year, 28 million female Internet users ages 18 and older with children in the household will use social networks at least once a month; the number of U.S. mom social networkers is expected to approach 30 million by 2017.

However, the growth in the number of U.S. social network using mom is expected to slow in the coming years as this demographic becomes saturated with users.