A PLN, or Personal Learning Network, are those resources that one uses to gather knowledge, inform their thoughts, and share that information with others. Traditional examples are newspapers, magazines, books, or face-to-face conversation with a friend over a cup of coffee. Today, for those that have embraced technology, one’s P.L.N. can be more complex. A technologically based P.L.N. consists of, among others:

WEBSITES
A website (alternatively, web site or Web site) is a collection of Web pages, images, videos or other digital assets that is hosted on one or more web servers, usually accessible via the Internet.

BLOGS
An abridgment of the term web log, a blog is a website, usually maintained by an individual, with regular entries of commentary, descriptions of events, or other material such as graphics or video. Entries are commonly displayed in reverse chronological order. "Blog" can also be used as a verb, meaning to maintain or add content to a blog.

INSTANT MESSAGING
Instant Messaging (IM) is a form of real-time communication between two or more people based on typed text. The text is conveyed via computers connected over a network such as the Internet.

Examples: AOL’s AIM, Google Talk, ICQ, Yahoo Messenger, Skype, Windows Live Messenger (MSN)

SOCIAL NETWORKS
A social network is a social structure made of nodes (which are generally individuals or organizations) that are tied by one or more specific types of interdependency, such as values, visions, ideas, friendship, kinship, etc. The resulting structures are often very complex.

SOCIAL NETWORK SERVICES
A social network service uses software to build online social networks for communities of people who share interests and activities or who are interested in exploring the interests and activities of others. Most services are primarily web based and provide a collection of various ways for users to interact, such as chat, messaging, email, video, voice chat, file sharing, blogging, discussion groups, and so on. Social networking has revolutionized the way we communicate and share information with one another in today's society. The main types of social networking services are those which contain directories of some categories (such as former classmates), means to connect with friends (usually with self-description pages), and recommender systems linked to trust.

Examples: MySpace, Facebook, Bebo, Skyrock Blog , Hi5, Orkut, Friendster, CyWorld

TWITTER
Twitter is a free social networking and micro-blogging service that allows users to send "updates" (or "tweets"; text-based posts, up to 140 characters long) to the Twitter website, via short message service (e.g. on a cell phone), instant messaging, or a third-party application such as Twitterrific or Facebook.

STUMBLEUPON
StumbleUpon is a web browser plugin that allows its users to discover and rate webpages, photos, videos, and news articles. These webpages are typically presented when the user who is known as a stumbler within the Stumbleupon community clicks the "Stumble!" button on the browser's toolbar. StumbleUpon chooses which new webpage to display based on the user's ratings of previous pages,ratings by his/her friends, and by the ratings of users with similar interests. i.e. it is a recommendation system which uses peer and social networking principles.

FLICKR
Flickr is an image/video hosting website, web services suite and an online communityWeb 2.0 applications. In addition to being a popular Web site for users to share personal photographs, the service is widely used by bloggers as a photo repository. Its popularity has been fueled by its organization tools that allow photos to be tagged and browsed by folksonomic means.