No, Your Sumo install code should only be used on 1 website domain.
Every Sumo registration are unique and given a SiteID number. While you can register as many SiteID's as you want, it's important to know which SiteID is used because it is tied to your subscription, campaigns, popups, and settings.
What about Subdomains?
If you have a subdomain, you can and should use the primary siteID associated with your account. That way all emails we send on your behalf and your stats we share with you about your domain reflect all of the website.
If you have Multiple Sites...
Your settings and data will not function properly when used on multiple websites. As nothing can be merged, transferred, or separated, you'll need to setup a new unique SiteID for each website.