A few of us withing our organization have been testing and using Chatter as a collaboration tool. We do not currently use Salesforce as our CRM. We're wondering if we will be able to retain our Chatter groups and posts if our company chooses to use Salesforce CRM.
Yes. Assuming you will not be starting a brand new Salesforce instance and instead are just upgrading user licenses to Premium CRM licenses. The beauty of the Salesforce Platform is that you can continually roll out new applications and features without interrupting current functionality. I'd highly recommend purchasing a sandbox instance so you can have even more separation between your current chatter use and the CRM rollout. If by "testing" Chatter you have a temporary Demo Org it is still possible but you may have to encourage your sales rep.