Social media day is a day to honor the force that social media and the people behind it have contributed to every day life. Social media has become more than just a fad, but a part of people's lives. From connecting with far flung friends and family, to friends you've never met to running a business social media plays a role in it all.
In honor of social media day there will be meetups all over the world. You can find a Meet up near you here. If you are unable to meet up in person you can of course participate in the event on social media. The official hashtag is #SMDAY and there's the official Facebook Page and Twitter.