Twitter: How can I form a set of related hashtags?

Now that I know I can no longer communicate with Twitter mashups out there, how can I create a set of related hashtags? For instance开发者_高级运维, how can I get all tags similar or related to yankees?

You might be interested in the mathematical equations for clustering related things.

Another, naive option, would be to just look at what hashtags frequently (subjective, I know) appear with a known hashtag and work from there.

You can use a term extractor on set of tweets returned by the topic of your choice. Eg: Get the list of tweets for search query 'yankees' and apply term extractor on the set of tweets you have. You can find Term Extraction APIs from Yahoo! and AlchemyAPI.

The result would set of important terms used in the tweets and you can use them with a hash to search for more related information.