For me the most obvious example of an online community would be Facebook. Initially developed in 2004 as a Harvard University social networking site for students, it has succeed exponentially since then, with a gaining of 845 million active users worldwide.
The reason for popularity is that it projects itself as a new communications means. Unlike phones, and emails, users have more alternatives of connecting and communicating with others. Facebooks offers platforms whereby people are able to create personal profile, join groups that share the same interest, share photos and videos with others and most importantly provide an opportunity to connect with others living in different parts of the world. Most recently, Facebook has develop an online phoning system on the Facebook app, where people are able to call others freely by using the Wi-Fi connection oppose to paying for their calls.
The downfall of Facebook or any other social network provider for that matter, is the legitimises of some of these personal profiles. People can steal and claims others information and photos as their own. Although Facebook has a system where people are able to report the incident, it is not always taken down. Another disadvantage are known as trolls. Trolls are people who post abuse on others profile causing people to feel an immense amount anxiety stress and a times suicidal. The problem is there a certain anonymity within Facebook, where it is difficult to retrieve an accurate identity of someone. Plus as Facebook has confidential obligation, it will not always, unless under special circumstance, i.e. organized crime or terrorists, reveal the true identity others.