At the heart of Twitter are short messages called Tweets — just like this one — which can include photos, videos, links, text, and #hashtags!
Connect with friends, family and other people you know. Share photos and videos, send messages and get updates.
Your Gravatar is an image that follows you from site to site appearing beside your name when you do things like comment or post on a blog. Avatars help identify your posts on blogs and web forums, so why not on any site?