Blogs (cutting expressions of "weblog") are discussion websites or information published on the World Wide Web which consists of discrete and frequent diary-style text entries ("posts"). Posts are usually displayed in reverse chronological order, so the most recent posts appear first, at the top of the web page. Until 2009, blogs were usually the work of one individual, sometimes from small groups, and often included a subject or topic. In 2010, "multi-author blogs" (MABs) were developed, with writings written by many authors and sometimes edited professionally. MABs from newspapers, other media outlets, universities, think tanks, advocacy groups and similar institutions are responsible for increasing the amount of blog traffic. The emergence of Twitter and other "microblogging" systems helped integrate MAB and single author blogs into the news media. Blogs can also be used as verbs, which means maintaining or adding content to the blog.
The emergence and growth of blogs in the late 1990s coincided with the emergence of web publishing tools that facilitate the posting of content by non-technical users who do not have much experience with HTML or computer programming. Previously, knowledge of technologies such as HTML and File Transfer Protocol was needed to publish content on the Web, and as such, early Web users tended to be hackers and computer enthusiasts. In 2010, the majority were interactive Web 2.0 sites, allowing visitors to leave online comments, and this interactivity distinguishes them from other static websites. In that sense, blogging can be seen as a form of social networking services. Indeed, bloggers not only produce content to post on their blogs, but also often build social relationships with other readers and bloggers. However, there are high-readers blogs that don't allow comments.
Many blogs comment on certain topics or topics, from politics to sports. Others function as more personal online diaries, and others function more as online brand advertisements from certain individuals or companies. Regular blogs combine text, digital images, and links to other blogs, web pages, and other media related to the topic. The ability of readers to leave comments that can be seen by the public, and interact with other commentators, is an important contribution to the popularity of many blogs. However, blog owners or writers often moderate and filter online comments to remove hate speech or other offensive content. Most blogs are primarily textual, although some focus on art (art blogs), photos (photoblogs), videos (video blogs or "vlogs"), music (MP3 blogs), and audio (podcasts). In education, blogs can be used as learning resources. These blogs are referred to as edublogs. Microblogging is another type of blogging, which displays very short posts.
On February 16, 2011, there were more than 156 million public blogs available. On February 20, 2014, there were around 172 million Tumblr and 75.8 million WordPress blogs in the world. According to critics and other bloggers, Blogger is the most popular blogging service used today. However, Blogger does not offer public statistics. Technorati registered 1.3 million blogs on February 22, 2014.