Can I run the integration in more than one Salesforce Org?

It is technically possible to install our product in multiple Salesforce orgs.  But there are some considerations which we have detailed below.

Testing
You can install our integration into one or more Salesforce Orgs.  For example production and a sandbox.  We never recommend connecting your sandbox to your live Campaign Monitor account.  Instead, you can set up a pay-as-you-go account to protect your data. Out of the box, the integration will push data from Campaign Monitor to your Salesforce org. However, triggers will be active so for example if you were to change an email address in Salesforce that could update Campaign Monitor incorrectly.

Connection the same Campaign Monitor account to more than one production org.
As mentioned above this is technically possible, and we have seen some valid use cases.  However, it is important to understand that generally, Salesforce is your source of truth for client data.  By having two Salesforce orgs you complicate this.  For example, you could have the same person in both Salesforce orgs with different details.  If you are updating Campaign Monitor with Salesforce data using our import wizard or field mappings data could be inadvertently affected.