Where are your clients increasingly hanging out in the social media world? Facebook isn’t the only place.

Pinterest, in particular, is growing rapidly, seeing its Web traffic surge nearly 50 percent in February compared to January, according to recent data from Experian Hitwise. The site now ranks as the third-most-popular social media site, behind Facebook and Twitter. What’s more, the site has been growing as a source for referrals to other Web sites: Pinterest users referred traffic to more Web sites in January than Google+, LinkedIn, and YouTube combined, according to a separate study by the site Shareholic. 

Ninety-one percent of adults online use social media sites regularly, according to the report. 

Experian Hitwise reports the following top six social media Web sites, based on total visitors from March:  

1. Facebook: 7 billion
2. Twitter: 182 million
3. Pinterest: 104 million
4. LinkedIn: 86 million
5. Tagged: 72 million
6. Google+: 61 million