Twitter is a text-based medium that allows you to publish statements of up to 140 characters — which includes letters, numbers, symbols, and spaces. Within each statement you may provide a link to a website or using Twitpic or other tool, a link to a photo.
Twitter is a good vehicle to have short conversations with other Tweeters, to broadcast a short or urgert message, to announce an event, or to draw new audiences to your blog or website.
Twitter accounts are free and viewable to the public unless you choose the “protected” option on your profile page.