The Medfield Public Library is hosting a free class on this year’s social media strategies and trends at the library Tuesday. This session will be conducted by Tammi Jacobson, a business adviser with the Massachusetts Small BusinessDevelopment Center, and aimed at small businessowners who know that having an online presence is necessary. The class will discuss business opportunities presented by websites, blogs, and social networks such as Facebook and Twitter. Other topics for the evening include using “the cloud,” texting, and QR codes. The session begins at 6:30 p.m. and is followed by a networking session from 8 to 8:45 p.m. The series continues with a social media for nonprofits class on Feb. 26 with Mare Parker O’Toole, a webmaster and technology trainer. The final session, on job interviews, will be held March 26 with Bill Napolitano, the founder of the Institute for Business Excellence, a training and development firm. You can register online for the Tuesday class at www.medfieldlibrary.org/2013/01/social-media-strategies-trends-in-2013-tue-jan-22nd-630-8pm. For more information, contact the library by phone at 508-359-4544 or e-mail at email@example.com.