Social networking has evolved from early platforms like AOL and personal websites to modern platforms like Facebook and Twitter. It began by focusing on communication and connecting with others but now supports sharing photos, videos and other content. Early social networks were exclusive to certain demographics but became more open and mainstream over time. Privacy is becoming a bigger concern as more personal information is shared. Social networking is also becoming pervasive across other websites and on mobile. It will likely split into separate layers and networks in the future to better support different types of relationships and sharing.