A hashtag is a word or phrase that is used in order to group posts on Twitter. The word or group of words connects to the topic you are tweeting about. You can use a hashtag by first typing the pound sign (#) and then typing the word or phrase that describes what you are tweeting. This allows users to click on the hashtag and view all related posts that have the same hashtag. For example, if I wanted to see everything that was happening in River Forest District 90, I could search #D90learns and every post that has this hashtag appears. You have to type in the hashtag in order for your post to be linked to the topic. You can use more than one hashtag in a post. Hashtags are also used when there are Twitter chats so that you can follow and participate in the conversation.