Social media is an emerging marketing trend that leverages Internet-based tools for sharing and discussing information among human beings. While the term is pretty broad and has roots from the 4 P’s of Marketing, it now most often refers to activities that integrate technology, content, social interaction, pictures, videos and audio. This interaction, and the manner in which information is presented, depends on the varied perspectives and "building" of shared meaning among communities, as people share their stories and experiences.

Social media marketing related to Internet marketing, Social Media refers to a collective group of web properties whose content is primarily published by users, not direct employees of the property (e.g. the vast majority of video on YouTube is published by non-YouTube employees). Social media optimization  is an element of a social marketing strategy that tries to get one's content more widely distributed across multiple social media services.

Social media marketing has two important aspects. The first, SMO, refers to on-page tactics through which a webmaster can improve a website for the age of social media. Such optimization includes adding links to services such as Digg, Reddit and Del.icio.us so that their pages can be easily 'saved and submitted' to and for these services.

Social media marketing, on the other hand, is about building ways that fan’s of a brand or company can promote it themselves in multiple online social media venues.

Some social media marketers offer to write content that is remarkable, unique, and newsworthy. This content can then be marketed by popularizing it or even by creating a “viral” video on YouTube and other video sites, including getting involved in blogs, forums, and niche communities. Others in the social media world consider this form of social media marketing a virtual grass roots effort.

Examples

Social media can take many different forms, including Internet forums, weblogs, wikis, podcasts, pictures and video. Technologies include: blogs, picture-sharing, vlogs, wall-postings, email, instant messaging, music-sharing, crowdsourcing, and voice over IP, to name a few.

Examples of social media applications are Google Groups (reference, social networking), Wikipedia (reference), MySpace (social networking), Facebook (social networking), Youmeo (social network aggregation), Last.fm (personal music), YouTube (social networking and video sharing), Avatars United (social networking), Second Life (virtual reality), Flickr (photo sharing), Twitter (social networking and microblogging) and other microblogs such as Jaiku and Pownce. Many of these social media services can be integrated via social network aggregation platforms like Mybloglog and Plaxo.

Social media software applications

Examples of social media applications include:

Communication

• Blogs
• Microblogs 
• Social Networking
• Events

Collaboration

• Wikis: Information Source
• Social bookmarking
• Social News Sites

Multimedia

• Photo sharing
• Video sharing
• Livecasting
• Audio and Music Sharing

Entertainment

• Virtual worlds
• Online gaming
• Game sharing