Social media allows people to gather and express themselves online. However, platforms need a critical mass of users to be successful and must allow unfettered self-expression or users will migrate elsewhere. Examples of successful social movements organized through social media include photo sharing on Flickr, protests in virtual worlds like Second Life, and political organizing on Facebook and Twitter. When starting a social media presence, it is best to begin small on one platform and engage consistently before expanding to multiple interconnected platforms and attracting a broader audience.