The total number of accounts that can be added to a user's list was cut to 400 from 1,000, the San Francisco-based internet firm said.
"Follow, unfollow, follow, unfollow. Who does that? Spammers," the Twitter safety team said in a tweet.
Tech giants warn Australia against law to break encryption
"So we're changing the number of accounts you can follow each day from 1,000 to 400. Don't worry, you'll be just fine."
Software programs referred to as "bots" sometimes run Twitter accounts, automatically following massive numbers of real people, a portion of whom tend to reciprocate by following back.
High follower counts can then serve to raise the status of bot accounts, which can fire off-website links or marketing content in tweets or messages to followers.
Tech firms should be made liable for ‘fake news’ on sites
Twitter policy bars use of the service for spreading spam, which it defines as "bulk or aggressive activity that attempts to manipulate or disrupt Twitter or the experience of users on Twitter to drive traffic or attention to unrelated accounts, products, services, or initiatives."
Factors taken into account by Twitter when determining if accounts are being used for spam is following and or unfollowing large numbers of accounts in short time periods.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ