Blogwebsite (see net jargon). A blog allows anyone (or almost anyone) to write a new webpage or add links.
This openness makes a blog good for discussion — if someone writes something that isn't right, someone else can correct it (but someone else cannot change it as in a wiki). For this to succeed, there must be a number of people interested in a topic of discussion. These people form a community that can discuss a topic or advocate a point of view.
However, it also means that those who have one point of view not shared by many other people can come back again and again and keep making the same argument over and over again. This is sometimes called flaming. All of this remains visible to everyone, and it is not common to remove a page.
In practice, a blog almost always shrinks to a small creative network of contributors (writers) who know and trust each other, plus a larger social network who just read it. Some blogs have scoring (evaluation) of posts that reinforces this network even more, so that those who are disagreed with, will become invisible.
Some experts think a blog has a power structure like that inside a political party, where a clique (a small, exclusive group of people) will dominate discussions by choosing when someone has "won" an argument, and when some matter is "decided".
Contrast: wiki, crit, email list