Blogs have taken the web by storm. They have allowed all kinds of people, interested in the most varied subjects, to communicate and interact with each other. The posting styles that bloggers use can be very different, and I have identified two major styles.
Some bloggers seem to prefer short posts, usually a personal comment backed by one or more supporting outbound links. Others prefer long posts, usually more elaborate dissertations that may or may not include outbound links.
The short posting format is easy to write and read. Everybody with a strong interest in a certain topic will probably know of many good articles, citations, resources and products related to that topic. It is not hard to launch a blog about that subject, and steer readers in the right direction via regular short comments sprinkled with useful outbound links.
If done properly, this kind of format is conducive to turning a blog into a "hub" (a site that offers many useful outbound links). The drawbacks of this style are that the outbound links will send visitors away. Also, short posts don't usually get many inbound links and are harder to index by the search engines. This means that short posts will usually have trouble ranking very high. On the possitive site, if you post relevant comments regularly and send your visitors to useful resources, they are likely to come back often.
The second format, the long post, is usually an article about a specific topic. Instead of pointing readers to other resources, the post itself is the resource. This type of post is more difficult, since not all bloggers have the ability to write long, articulate, compelling pieces. Long, well written articles, tend to attract inbound links and raise the link popularity of the blog where they are posted, therefore they are more likely to rank high in the search engines. Long posts made of original content will turn a blog into an "authority" (a site that other sites in the same topical community link to).
It is not uncommon to find bloggers using both posting styles. In fact, I believe that the combination of short posts and long posts is the format that is best suited to make the blog more interesting and valuable for readers and search engines alike.