A blog (short for Web log) is a Website in which items are posted and displayed with the newest at the top. Many blogs allow visitors to post responses to "blog postings" created by the founder of the blog or by other contributors who have been given posting privileges by the founder.
Like other media, blogs often focus on a particular subject, such as food, politics, or news. Some blogs function as online diaries, and until recent years, that is how most of them functioned.
A typical blog combines text, images, and links to other blogs, Webpages, and other media related to its topic. Since its appearance in 1995, blogging has emerged as a popular means of communication, affecting public opinion and mass media around the world.
Blogs can be hosted by dedicated blog hosting services, or they can be run using blog software on regular Web hosting services.
Blogger.com allows users free access to create blogs of their own. Myspace.com is another popular service, which allows users to blog, and to also post music clips, photos and videos to a site. Yahoo Groups allows a form of blogging in which photos, pictures and files can be uploaded and viewed by visitors or by a select group in which .
Many blogs are still used as online journals, and most recently, as social networking sites. But this is not always the case. Companies and employees are both seeing blogs as potential ways to communicate.
A blog has public relations applications as a communications tool between internal and other internal publics or between internal and external publics.
- Blogs can function as one of the official means by which a company - or the head of a company - communicates information to employees, and receives feedback from them in return. Bob Lutz of GM often posts on the company's FastLane Blog
- Blogs can be used as ways to introduce or test the waters for new products and services. Google often does this.
- Blogs have been effectively used by newspapers to speak to readers and gauge responses to stories and to even solicit story ideas
- Blogs serve as a way to clear up misunderstandings and can back up the work of a Crisis management Team during a crisis
Problems and dangers
There are several problems and potential dangers to using blogs in corporate settings, or for public relations purposes.
- As a completely free form of communication, you cannot judge the response to postings
- "Trolls" - or those who post material simply to provoke a negative response - may use the blog in obscene or provocative ways, sometimes using profanity
- Most blogs allow anyone to post without signing in. These anonymous postings may promote this trolling behavior.
- A blog may be created and used by a disgruntled employee to make comments against your company
- Blogs can very quickly spread rumors, heighten public anxiety and put out misinformation (sometimes libelous) about you or your company
- Employees could use the blog to inadvertantly (or not) release confidential or damaging information about the company or individuals within it, including financial information  
- Information in blogs tends to remain online forever, even if inaccurate, and even if the poster removes it, making false information permanent
- Companies have used "moles" to post positive messages about the companies on various blogs, only to be accused of manipulation when discovered
- Be respectful of your colleagues
- Get your facts straight
- Provide context for your argument
- Engage in private feedback (i.e. via email, without posting to the blog)
Employees who blog without guidelines can compromise their company's reputation, or could at the very least face angry employers - perhaps unfairly. []