Web logs (BLOGs) are Web pages made up of usually short, frequently updated posts that are arranged chronologically. What's in a blog can be anything from links, commentary, personal reflection, photos, poetry etc.
Many blogs are personal, and feel like someone's personal diary. Others are collaborative efforts based on a specific topic or area of mutual interest.
Blogs are also excellent group communication tools. They can be used privately on an intranet to allow members of the group to post related links, files, quotes, or commentary.