When creating a List in FrontSpin, it will ask you to choose a List Type: Static or Dynamic.
Static vs. Dynamic:
Since FrontSpin Lists are powered by Salesforce Reports, setting the List Type to Dynamic allows it to be refreshed (re-running the Salesforce Report), which will automatically update the Leads and Contacts in the List. This allows new Leads or Contacts that match the Salesforce Report criteria to come into the List, and any that no longer match the Salesforce Report criteria will be removed from the List.
Setting the List Type to Static, on the other hand, only allows the data to come into the List one time; it is not refreshable. This List Type may be used, for example, when you want to create an guest invitation list for a conference or event, where the List itself would not need to be refreshed or changed.