Blog
A blog is a journalistic website in which a "blogger" (web author, or site administrator) posts entries. Often, entries are displayed in reverse-chronological order.
Etymology
"Blog" is a shortening of "web log". Blog can also be used as a verb to refer to adding an entry about a topic to a blog, as in "I blogged about that". The originator of the word is disputed, but it originated in the late 1990s.
Technical Preconditions
Many bloggers use a hosted blogging service, like Blogger or TypePad or LiveJournal, which allow the blogger to get started without installing any software on their computer. Some of these are ad-supported, and some offer paid ad-free models.
There are also dozens of blogging programs a user can install on his own computer, using a personal machine as his blog's server. These allow the blogger to decide whether or not to allow advertising for income but require the blogger to shoulder his hardware and bandwidth costs.
Business Model
Although most blogging is done for fun or for informational purposes, some blogging is done for monetary reasons.
Some businesses run blogs, where their CEOs or other ranking officials can write to the public, their customers, and to shareholders. Some of these blogs are actually written by the executive, but many are ghostwritten by staffers or assistants. This model is also followed by political candidates.
Some bloggers accept money to do promotion for a company or its products without disclosing the arrangement. For instance, a blogger working for a company or a PR firm might write a favorable review of a product, refute accusations against the company, or smear rivals in exchange for money. Such actions are called astroturfing, and are generally discouraged in the online community, as they represent an attempt to create "fake grassroots", and astroturfers are denounced if and when discovered.
Finally, some bloggers with a large enough audience can make money off of pay-per-click advertising and selling merchandise.
Accomplishments of Bloggers
Integrating Web 2.0 services
Bloggers may make use of collaborative web tools in their blogs. For instance, many bloggers store videos related to their posts on Youtube or Google Video and photos on Photobucket or Flickr. They link to other blogs, and find many of their stories on other collaborative websites like Digg, which in turn finds and highlights interesting blog stories.