A report from Twopcharts, a website that monitors Twitter account activity, states that about 44% of the 974 million existing Twitter accounts have never sent a tweet.
Twopcharts, which provided some data about tweeting activity last month, is unable to track when someone has logged into their account. It can only tell when the account retweets or tweets its own message.
Twitter said it has 241 million monthly active users the last three months of 2013. Twitter defines a monthly active user as an account that logs in at least once a month. By Twitter’s standards, a person does not have to tweet to be considered a monthly active user.
To be sure, people don’t have to actively tweet to find the service useful. There’s more than enough stuff to read on almost any topic in the world on Twitter to keep users occupied."