1 - Search API
Twitter has a search API:
- http://search.twitter.com/search.atom?q=twitter until:2009-03-01 (Until a date. You may also use from: date)
Limitations: most 100 for each call
2 - Tweet
- limited to 140 characters of text
- Language: The frequency of misspellings and slang in tweets is much higher than in other domains.
- Domain (variety of topics such as movie reviews) are much higher
3 - Retweet
Retweeting is the process of copying another user's tweet and posting to another account. This usually happens if a user likes another user's tweet. Retweets are commonly abbreviated with RT.