I have a list of marketing/advertisement campaigns that lists the current and planned ad campaigns, start dates, end dates, and other various info. Is it possible to roll the list items from this custom list into a timeline or is the timeline specific to task lists?
2013 task lists have the new time line associated with that content type. Otherwise Ghantt chart views work with any other lists, given the correct info such as start / end dates. There is also the task list timeline web part that can showcase the items from the task list.