If you've had enough of Twitter and don't plan to use your account again, schedule your account for removal from the Account Settings page on the Twitter website. If you just want to minimize updates, you don't need to wipe out your entire profile, however -- instead, unfollow a few people to clean up your timeline or turn off SMS notifications for specific users.
Unsubscribe From Texts
To cut the number of text messages Twitter sends, turn off text notifications for individual users. Send "OFF" followed by a user's name (without "@") to "40404" to disable texts from that user. This method won't unfollow the user, so you'll still see his tweets on your computer. Send "OFF" without a username to turn off all texts from Twitter. If you want to turn off notifications for several users without sending multiple texts, visit your Following page (link in Resources) from a computer and use the Settings menu by each user's name.
Unfollow a User
Unfollowing people on Twitter stops you from seeing their updates on your Twitter timeline. Click the "Following" button on a Twitter user's page to unsubscribe. Even after you stop following someone, you can still open her Twitter page directly to read her updates.
Delete Your Account
To completely unsubscribe from Twitter, open the Account Settings page (link in Resources) and click "Deactivate My Account." After you confirm the request, Twitter schedules your account for removal in 30 days. Log back in before that time expires to cancel the deletion. (See Reference 3.) If you have only ever used Twitter through text messaging, delete your account by sending "STOP" to "40404." (See Reference 1.)