In embodiments of the present invention improved capabilities are described for a computer system for organizing in-person gatherings of users of topic-related interest, comprising a web-based meeting management facility having a user interface accessible to multiple users, wherein each of the multiple users may use the user interface to join at least one of multiple meeting groups based on at least one of topic-related interest and geographic locale, where a user becomes a member when they join the meeting group; and a server-based progressive announcement facility for enabling an organizer to control a time-staged meeting announcement release related to a meeting group based on an announcement delivery parameter, wherein the time-staged meeting announcement release includes multiple time-staged meeting announcements each including at least one user within the multiple users.