How do you define a blog

I have been building and designing web sites for nearly twelve years but only recently started getting interested in all things blog.

The interesting thing for me about blogs is how people try to define them. In the same way Web 2.0 has received numerous people and companies telling us what it is blogs are also often described in various ways
I have tried to define blogs in two distinctive ways :
1 (a to m) : from both a functional and technical perspective
2 (a to h) : from a conceptual and slightly more emotional perspective

The Main characteristics :
1a) Title, each post/article/note will have a title
1b) Date (optionally time), each post/article/note will display the date and often the time at which it was created.
1c) Content/Body, each post/article/note has content that is the main body, however it is possible in rare cases that the title and content be the same length.
1d) Comments, each post/article/note usually allows users to post comments. Some systems have central user authentication systems that will recognize users and authenticate them so they can post as a recognized user. However really good blogs have sometimes been lead to switch off comments due to splog (spam on blogs) or an overwhelming amount of comments posted.
1e) Permalink, each post/article/note has a specific URL/address that will display the post/article/note in full and generally followed by the comments

The Common Options :
1f) Author, articles/posts/notes will usually display the name of the author or the nickname/handle of the author
1g) Categories/Tags, when each post/article/note is created, the creator frequently indicates which categories/tags it is associated with.
1h) Trackback, blogs are the precursors in this area; the trackback is essentially an automated communication system that will inform other blogs/system/servers that a message has been posted about a post/article/note. When a post/article/note is written on blog A about something on blog B, blog A automatically pings blog B to inform it.
1i) Archives, blogs often have links to archives and or previous articles/posts/notes sorted by months. This is sometimes presented like a calendar
1j) Order, blog comments are usually displayed after the post/article/note, in reverse chronological order (the most recent one is displayed first)

Back-end Functions :
1k) Users or groups of users are authenticated and can then gain access to a type of dashboard/panel that will allow them to create and often preview before publishing the post/article/note.
1l) Categories/Tags, Pages and of course the articles/posts/notes can be managed using a WYSIWIG system or a form based system in the same manner that articles/posts/notes can be created
1m) Themes and Plugins, Many popular blog systems allow bloggers to heavily customize/personalize the look and feel of their blogs on top of allowing them to add specific functions like contact pages, photo galleries etc.

The Conceptual and Emotional Perspectives :
2a) Opinions, blogs are often regarded as being fairly personal on par with diaries and journals some very interesting ones are political oriented.
2b) Theme, blogs and the content published often has a central underlying theme or a group of bloggers will publish on a common topic.
2c) Types, blogs are often either professional or personal and less frequently can be group based
2d) Discussion, blogging is closely associated with the idea of discussion via the concept of posting comments about the post/article/note. There is play side of blogging following the concept of 'frenemies' (friends and enemies) that mutually poke each other to create hype around their mutual blogs. However this practice often leads to futile flame contests that lack real value in the long run.
2e) Personal, blogs often present themselves as the work of a person or a group of people and do so with an about page and more often than not with a photo. This instantly gives personality and originality, creating a link/bond with the writer that is often lacking in many online newspapers/magazines.
2f) Free, on a par with the founding spirit of the Internet, blogs are so far, in the vast majority, free to create and use. This is one of the nice sides of blogging since it resembles a large freedom of speech movement. Specific and additional user needs like having your own domain name are evidently available but at a price...
2g) Easy to use, blogs do not really entail knowledge of any programming language and each new version of the popular systems make things easier and bring new interesting functions to the blogging world. A lot of networking functions like trackback to inform others of what you have posted are automatically handled without any user intervention required.

What Blogs are not :
Forums are not in most cases like blogs. In a forum, multiple users can post articles/content and multiple users can post comments. When you read a thread of posts in a forum it can be difficult to differentiate between the first post and the following posts. It would be possible to set-up a forum whereby the initial message in a thread could only originate from a specific user or group of users, then and only then, could others respond, however this is not how forums are usually set-up. Unlike blogs where discussions evolve from one point, forums allow multiple starting points for discussion. Blogs also seem to link far more between each other and between posts/notes than forums do. This habit most probably originates from the way search engines look at incoming and site wide links in the way they rank sites.

Newsgroups are probably the furthest from blogs. Newsgroups are not only different in form but also technically and functionally. Groups on newsgroups are replicated over multiple servers all over the world which rarely happens with blogs in fact I can' think of an example. Newsgroups are just messages posted to a specific group and depending on the software it can be very hard to distinguish links and/or associations between messages unlike in forums. There is no real structure for posting comments about an initial post in newsgroups since links between posts are difficult to establish. Newsgroups are also well known for multi-part binary posts of images, video and all sorts of other file formats on top of text messages.

CMS, I've worked on creating web sites using Content Management Systems (CMS) like Vignette StoryServer and recently Gossamer Threads Links (used to create this web site). With this experience in mind I tend to disagree with most blog fanatics in their will to differentiate themselves with CMS systems. There is no real need to debate here, professional CMS software is capable, when properly configured, to provide everything that blogs can provide, and more (hence the extra cost involved).
Nearly all real CMS can be set-up to look and work exactly like blogs. From this point onwards blog fanatics tend to turn to the conceptual and more emotional definitions above to argue differences between a CMS and blogs which can obviously also be replicated...

Blog Trivia :
One of the first bloggers Justin Hall started with a site called links.net
Web log was first used in 1997 by Jorn Barger and was first shortened to blog in 1999 by Peter Merholz
Open Diary first started the article with comments system in 1998