Say, for instance, that you want to assign a tag to a new product that Google released. To find the official hashtag, type "Google" into Hashtag.org's search bar. It will return results with a list of Google-related hashtags.

The site also keeps analytics for popular tags, showing recent messages in which people used the tag, the people who tweeted it, and related tags.

The Twitter community organically and collectively decides what a hashtag should be as it pertains to a certain topic. Third-party sites, such as and allow Twitter users to define hashtags. facilitates discussions around how certain hashtags should be defined and formed.

All of these user-generated sites have drawbacks. For one, they often fail to return definitions for common hashtags on Twitter. This could be due to the fact that some are really obvious - if you type #facebook into tagulus, for instance, no results appear, as no one bothered to take the time to note that it would be used for a tweet about the social network.