Social Media Twitter increases DM character limit, Periscope and Snapchat continue to grow Users can now send 10,000-character private messages. In light of recent data, PR and marketing pros might also want to join Periscope and Snapchat. By Beki Winchel@bekiwekiAug. 14, 2015 SHARE To read the full story, log in. Become a Ragan Insider member to read this article and all other archived content. Sign up today Already a member? Log in here. Learn more about Ragan Insider.