A variation of a method for serving interactive content includes: inserting a parent card into a visual element; inserting a set of child cards over the parent card in the visual element, each child card including advertising content related to the parent card; in response to a swipe over the visual element following insertion of the visual element into a document rendered on a display, indexing through the set of child cards rendered over the parent card; in response to selection of a child card, triggering the computing device to open an expanded window over the document; rendering expanded variants of child cards within the expanded window; in response to a swipe over the expanded window, indexing through expanded variants of the set of child cards rendered; and, in response to selection of an expanded variant of a particular child card, triggering the computing device to navigate to an external document associated with the particular child card.