What Are Hashtags (“#” Symbols)?

Using hashtags to categorize Tweets by keyword:

• People use the hashtag symbol # before a relevant keyword or phrase (no spaces) in their Tweet to categorize those Tweets and help them show more easily in Twitter Search.
• Clicking on a hashtagged word in any message shows you all other Tweets marked with that keyword.
• Hashtags can occur anywhere in the Tweet – at the beginning, middle, or end.
• Hashtagged words that become very popular are often Trending Topics.

Example: In the Tweet below, @eddie included the hashtag #FF. Users created this as shorthand for “Follow Friday,” a weekly tradition where users recommend people that others should follow on Twitter. You’ll see this on Fridays.

Using hashtags correctly:

• If you Tweet with a hashtag on a public account, anyone who does a search for that hashtag may find your Tweet
• Don’t #spam #with #hashtags. Don’t over-tag a single Tweet. (Best practices recommend using no more than 2 hashtags per Tweet.)
• Use hashtags only on Tweets relevant to the topic.

Reference: twitter.com