Abstract: Systems and methods for dynamic server-based filtering that selectively deletes or delivers received messages or summary information therefor, based upon the characteristics of the received messages and the filtering rules implemented by the server. In one embodiment, a server receives electronic messages addressed to a client and applies a set of filtering rules to the messages to categorize them into groups of wanted, unwanted, and preview messages. Wanted messages are delivered in their entirety without further input. Unwanted messages are deleted without further input. Summary information is delivered for preview messages. A user provides feedback indicating that the corresponding message should be delivered in its entirety, or deleted. The deliver or delete decision can be applied to one message, or to all similar messages. The server takes action according to the feedback, updates its filtering rules and credits the user's account, as appropriate.