Regardless of the category used (Tweets, Direct messages, Lists), configurations should each be between 2 and 320 characters long. 

For example:

("Authors OR #writing" for example, is 17 characters long)

 For the Lists category, the List owner and List name do NOT count against the amount of characters you can use:

Here "TechCrunch" (Twitter username) and "writers" (List name) are NOT included in the amount of characters allowed. Only the keyword part (which is optional): "#tech OR technology" count for the number of characters you can place in a configuration.

The following special characters are NOT allowed in the configurations: ` ~ ^ * = | ] } [ { ;