The length of time that Instant Messaging (IM) messages are stored can vary significantly depending on the service provider's policies. Some platforms may store messages indefinitely, while others might delete them after a certain period, such as 30 days, 6 months, or even immediately after they are read or sent.
For example, WhatsApp stores messages on their servers until the chat is deleted by the user. Similarly, Facebook Messenger retains messages for a period of time, but the exact duration can depend on various factors including account activity and settings.
In the context of cloud services, if you're looking for a solution that allows you to store IM messages for a longer period, you might consider services like Tencent Cloud's Message Service (CMS). This service provides a way to store, manage, and analyze messages, with customizable retention policies to suit your needs.