A blog (a truncation of the expression weblog) is a discussion or informational site published on the World Wide Web and consisting of discrete entries ("posts") typically displayed in reverse chronological order (the most recent post appears first). Until 2009 blogs were usually the work of a single individual, occasionally of a small group, and often covered a single subject. More recently "multi-author blogs" (MABs) have developed, with posts written by large numbers of authors and professionally edited. MABs from newspapers, other media outlets, universities, think tanks, advocacy groups and similar institutions account for an increasing quantity of blog traffic. The rise of Twitter and other "microblogging" systems helps integrate MABs and single-author blogs into societal newstreams. Blog can also be used as a verb, meaning to maintain or add content to a blog.
The modern blog evolved from the online diary, where people would keep a running account of their personal lives. Most such writers called themselves diarists, journalists, or journalers. Justin Hall, who began personal blogging in 1994 while a student at Swarthmore College, is generally recognized as one of the earlier bloggers, as is Jerry Pournelle. Dave Winer's Scripting News is also credited with being one of the older and longer running weblogs.
The personal blog is an ongoing diary or commentary written by an individual.
A type of weblog in which posts are written and published by more than one author. The majority of high-profile collaborative blogs are based around a single uniting theme, such as politics or technology.
Microblogging is the practice of posting small pieces of digital content—which could be text, pictures, links, short videos, or other media—on the Internet. Microblogging offers a portable communication mode that feels organic and spontaneous to many and has captured the public imagination. Examples of these include Twitter, Facebook, Tumblr, and by far the largest WeiBo.
A blog can be private, as in most cases, or it can be for business purposes. Blogs used internally to enhance the communication and culture in a corporation or externally formarketing, branding or public relations purposes are called corporate blogs. Similar blogs for clubs and societies are called club blogs, group blogs, or by similar names; typical use is to inform members and other interested parties of club and member activities.
Some blogs focus on a particular subject, such as political blogs, health blogs, travel blogs (also known as travelogs), gardening blogs, house blogs, fashion blogs,project blogs, education blogs, niche blogs, classical music blogs, quizzing blogs and legal blogs (often referred to as a blawgs) or dreamlogs. How To/Tutorial blogs are becoming increasing popular
A blog comprising videos is called a vlog, one comprising links is called a linklog, a site containing a portfolio of sketches is called a sketchblog or one comprising photos is called a photoblog. Blogs with shorter posts and mixed media types are called tumblelogs. Blogs that are written on typewriters and then scanned are called typecast or typecast blogs; see typecasting (blogging).
A Reverse Blog is composed by its users rather than a single blogger. This system has the characteristics of a blog, and the writing of several authors. These can be written by several contributing authors on a topic, or opened up for anyone to write. There is typically some limit to the number of entries to keep it from operating like a Web Forum.