A weblog, or “blog”, is a personal journal on the Web that is updated frequently, most often displaying its material in journal-like chronological dated entries or posts.  Weblogs cover as many different topics, and express as many opinions, as there are people writing them. Weblogs are different from traditional media. Bloggers (someone who writes a blog ) tend to be more opinionated, niche-focused, and partisan than journalists, who strive for editorial objectivity. Many weblogs allow readers to write a reaction (comment) to what was written in the blog entry. A blogroll is a list of blogs and bloggers that any particular blog author finds influential or interesting. The online community of bloggers, their writings and the comments is called Blogosphere.

Weblogs usually offer RSS feeds (a file format that allows anyone with a website to easily “syndicate” their content)  to make part of their content (excerpts and links back to the originating website) available to other sites to use and publish the informations. Excerpts are optional hand-crafted summaries of the content. To provide an easy way to capture specific references to posts or articles in a blog, permalinks (a permanent identifier to a specific weblog post or article) are the preferred solution. Inbound links refer to hyperlinks from other sources citing that weblog. Outbound links refer to hyperlinks from the weblog to outside sources. The leading monitor of the world of weblogs is Technorati, a real-time search engine that is the largest source of fresh information about the global and local conversations going on all across the Web.