A method, a computing device and a computer program product are provided. A content pool view is displayed on a display. The content pool view includes a node retain area and a node delete area. The node retain area has a number of retention periods for retaining contents of documents. Responsive to a user selecting a document via a computing device and dropping the document on a drop position in the node retain area, a node associated with the content of the document is displayed in the drop position of the content pool view. A retention period of the node is set based on the drop position in the node retain area. After a passing of a period of time, the node is moved toward the node delete area while decreasing the set retention period. Responsive to the node being moved into the node delete area, the node is deleted.