You can search by keywords, topic, author, language, and a variety of other criteria. Head on over to
Twitter Search to see this in action. Type a keyword that you want to search for (for example, Java™), and then click Search. Voilà! A series of tweets, newest to oldest, appears on the screen.
But how can you search by topic instead of by keyword? Keep in mind that tweets specific to a particular topic contain the topic name preceded by the hash symbol/pound sign (#). For example, a Star Trek enthusiast might tweet something about the new movie and within that tweet include #startrek to let people know that this particular tweet is about Star Trek.
To search for tweets by topic, simply include the topic name (including the hash symbol/pound sign) in your keyword search. Following the previous example, simply go to the Twitter Search page, type #startrek, then click Search. You will see a list of tweets specific to Star Trek.