Following and Unfollowing

• The automated mass following or unfollowing of people is not permitted on Twitter because it is a common tactic of spammers, who mass-follow people, and then mass-unfollow those who do not follow back. The only exception to this rule is that you're allowed to auto-follow-back people who follow you, with an application like Tweet Later. This is thought to help maintain followers, but following too many people can make your own timeline harder to keep up with.
  
  

Auto-Tweeting Feeds

• If you have your own blog, YouTube channel or other source of content online, automating the posting of updates to your Twitter feed is a good way to save time. However, note that you will not be able to personalize the tweet, which might be a useful way to highlight the best points of your content. Tweet Hopper and Feedburner's "Socialize" feature are two ways this can be done in practice.
  
  

Automated Retweets, Direct Messages and @ Mentions

• Generally speaking, automated retweets are frowned on, as the function exists to allow you to retweet something you decide your followers would like and automation takes the decision out of the equation. Automated @ mentions are disallowed for similar reasons, unless the recipient gave you permission. Finally, automated "Thanks for following" direct messages are allowed, which can be used to give followers a quick message or some words of wisdom. Tweet Later is an application that supports this function.
  
  

Automated Advertising

• Some people try to make money through Twitter, such as through sponsored tweets, where Twitter users are paid to tweet about certain products or spread affiliate links. Applications that automate this process are available; however, such tweets are permitted only when written manually by you. Third-party applications used to auto-tweet affiliate links or sponsored tweets are not permitted by Twitter and might result in account suspension.