Currently, Connections Cloud, unlike other services, has no limitation in terms of number of messages sent, data replication, or downloading of messages made by IMAP.
This does not mean that misuse of these services is not controlled. There are monitoring mechanisms to prevent abuses, in a way that an unreasonable use of a service is detected, or there is an use for something that has not been designed to work that way, the account/user that is making use of the service may be suspended (as reflected on service agreements). A clear example is the use of IMAP, as we have seen previously is not a mechanism designed for a mass of data extraction, since an indiscriminate use of it can affect the service. Obviously, if IBM detected that is doing such use not appropriate, could stop the service to avoid affecting other clients.
In order to standardize the service, are being gradually introduced so-called mechanisms of “rate limits” or “api throttling”, which restrict the number of calls that can be made to it directly in the API. So far, only APIs for Social (connections) had those protection mechanisms (limiting calls to the API that is could make per minute), but not the mail.
The first affected service will be sending massive post, so that a user cannot send more 5000 messages per day, or not more than 500 messages in a time of 15 minutes. They are figures that I find are very reasonable, and difficult to achieve, since Connections Cloud is not a mail to mass or transactional delivery platform (there are excellent tools for this purpose, such as Sengrid, Awever or MailChimp, or the more specific to mail with a strong component in professional marketing, the WCA – Watson Campaign Automation).
Note also that on this year roadmap, it is planned to have similar “API Throtling mechanism” for the other related services, in order to ensure the “healthy” Connections Cloud service, additional mechanisms, providing similar mechanism to the ones Google or Microsoft already have in place in its service (ie, replica, sync, bandwith usage, etc)