Providing temporary use of on-line non-downloadable software via an interactive web site that allows users to: (a) differentially upload, classify, label, tag and otherwise categorize and/or store electronic files and hyperlinks for selective access by others in accordance with group designations that are variable and dynamically defined by multiple user inputs; (b) define, request, block, schedule, confirm, annotate, change, and cancel meetings and other calendaring events using dynamic classifications, labels, tags and/or other categorizations of users and user data