I have often wondered what is a true blog. Lets find out.

I have read definitions like it should contain a calendar and / or it should be updated regularly and / or entries should be dated. Let's look at them in details.

This blog doesn't have a calendar. Does it prevent it from being a blog? Nowadays most blogs do not have a calendar. Calendar was relevant in the early days of blogging where blogs were few and people loved to stay on one blog and browse through previous entries using a calendar. Today it mostly takes up space. It surely cannot be a defining feature for a blog.

What about a website which contains dated articles on a specific topic? Does that alone make it a blog? If so then NY Times or SF Chronicle website should also be considered to be a blog.

When we talk about frequency of update, how do we define the threshold frequency which defines / undefines a blog? Frequency of update appears to be a narrow definition for a blog. Lot of blogs like Guy Kawasaki's infrequently updated blog would fail to make the list if frequency of update is the criteria.

However we all know when we see a blog. So what is a blog?

We cannot take away the date element from a blog because of its origin - web + log. It started as and even today it is a log or journal. The topic can however be diverse and not just limited to one's life.

A blog is an interactive medium. You can comment on a blog and even start a discussion. Some media companies nowadays have enabled discussion on their articles, thereby bringing them closer to a blog.

A blog may have one or more author like Boing Boing. That doesn't preclude it from being a blog.

Where does sydication fit in a blog definition? Online newspapers used to syndicate for ages. Today almost all blogs provide RSS / Atom feed for syndicating their contents. Is it required definition for a blog. Personally I don't think so. Syndication or pings are just ways to make your blog more widely available and read.

In conclusion, with some reservations, I think the best definition for a blog is:
A blog is a website with dated articles which allows viewer to comment on articles.