You can use Usetiful product tours on as many sites as you need. All sites can contain the same embed code.
Monthly active users (MAU) represent the number of users who visit a site within a specific period (typically month). Vendors that charge for MAU are charging you even if your visitors do not use their solution.
Assist is counted only when an user is actively helped by Usetiful. Everytime user activates a Usetiful element (such as product tour or smart tip), it is counted as assist. That way you are charged only for users that interact with Usetiful.
Your users won’t be affected during the current subscription period. We will notify you upfront and give you enough time to decide whether you wish to upgrade your subscription to a higher tier or to restructure your Usetiful content. If no action is taken, we will automatically upgrade your service to the respective tier with the new subscription period.