If you haven't heard of it yet, Twitter have two very important guidelines you should abide to prevent your account from being suspended. They are the Following Rules and Best Practices and the Automation Rules and Best Practices. I went trough these guidelines quite extensively, and here are the three reasons I find it'll get your account suspended.
1. Are You Inadvertently Spamming People?
Repeatedly sending the same link to several people in a short period of time is against Twitter Terms of Service. Even long time users of Twitter can get their accounts suspended for this reason. It does not matter if you're trying to create awareness to your service, blog or even a charity cause. Spamming users is against Twitter's guideline.
2. Are You Massively Following and Unfollowing Users?
Follow and unfollow users with the intention of gathering their attention or building a followers base is also against Twitter Terms of Service. You are most certain to have your account suspended if you're using an automated tool, but you're also at risk if your are manually following and unfollowing users in masses. The current Twitter Following Rules and Best Practices limit every account to 1,000 new followers a day, and there are even more restrictions if you're following more than 2,000 people.
3. Are You Creating Multiple Accounts?
This is certainly not the most common reason to have your account suspended. Nonetheless, best safe than sorry, if you think you have a valid reason for creating multiple accounts file a ticket support and explain what are you planning to do. You may get approval for that as there are legitimate reasons for a user to have more than one account.
Twitter is not preventing users from participating on the community, they are merely setting guidelines to protect their community and provide a better user experience. If you already got your account suspended simply file a support ticket and explain your situation. My guess is they'll gladly help you sort this out.
What about you? Have you got a Twitter account suspension story to tell?