Twitter has removed the character limit on direct messages sent using the social network, enabling users to send private user-to-user messages up to 10,000 characters in length in contrast to the short-form public posts allowed.

The move seems part of a growing investment in private messaging by the company, which recently enabled users to open up their private message inbox to any messages, when it was previously limited to communication between two users who were mutually following each other.

The move was announced on Twitters development blog, which also confirmed that Twitters public side would be remaining the same, with the existing 140 character limit on public status updates.

Given the fierce competition developing between OTT messaging apps and spin-off platforms like Facebook Messenger, Twitter is no doubt aware that instant messaging could offer it a huge market for growth if it can encourage people to adopt it as a messaging service.

However, with CEO Dick Costolo stepping down, its possible Twitter will change tactics again, and leave the messaging market to those with an already established presence.