What are #hashtags?

I believe hashtags were introduced by Twitter communities.

Basically, hashtags are tags that starts with # in Twitter posts. These tags will be treated as topics / events / groups that you are tweeting. If others are interested with your topics / events / groups, they will just search your hashtags. Find out more on the references below.

References

• #hashtags
• Tag (metadata)
• HOW TO: Get the Most Out of Twitter #Hashtags
• Tweet Your Message to a Larger Audience with Hashtags
• What the Hashtag?!
• Twemes.com