Anonymous is without identity, authorship, origin and individuality. That is the rough definition of the word, anonymous, according to Merriam-Webster online dictionary.
Anonymous is nothing more than an individual who likes to remain unidentified whether it be from the internet or the real world. The group known as Anonymous works the same way. The only difference is that the group Anonymous in cases a group of people rather than just one. Anon is also short for Anonymous which is widely used when referring to the group. Encyclopedia Dramatica has a more in depth description here. Anon is cruel, just, and promote truth.

The Original Anon
Nobody knows the origin of Anonymous for sure, but we do know that it was probably started on forums and image dumps like 4Chan. The goal of Anon originally was to make fun of, or embarrass people online. Some people will argue that the goal of Anon was to help keep stupid people off the internet. That is clearly debatable. Either way, Anon was first started with a purpose. Even though it is not clear at first, it has become very apparent with recent time.
Anon Today
Today, Anon has been accused of being terroristic in nature, but liberal at the same time. You will see both good and bad of Anon, which is where a lot of misconception comes in. Anyone can do something in the name of Anon, but that doesn't mean that Anon, as a group, is responsible for what happens. Some Anon like to troll the internet, some like to stock individuals and others like to protest what they believe in. It has become apparent that Anon is no longer just a group of people with a single purpose, but multiple groups with multiple purposes.
Misconceptions about Anon
A lot of people thing that Anon is about bomb threats, death threats and threats of many natures. This is just not true. Just because a splinter group from Anon involves themselves in terroristic behavior doesn't mean that all Anon is this way. Like I have said before, there are many different groups of Anon, but each one is different from one another. Fox11 was one of the first news stations to spread the word of Anon even though it is clearly exaggerated.
Anon in the Future
There has been some speculation to what will happen to Anon in the future. One such speculation is that Anon will enter into a civil war. There are so many different groups of Anon with different opinions; they tend to fight over what Anon is really about. Whether or not there is going to be a civil war, it is obvious a standard for Anon should be set to avoid such issues.