Techniques are disclosed for sharing information in a wide variety of
contexts. An information sharing system is described that allows both an explicit
capture process and an implicit capture process to add information items to a staging
area. Further, the information sharing system supports both implicit and explicit
consumption of information items that are stored in said staging area. A rules
engine is provided to allow users to create and register rules that customize the
behavior of the capture processes, the consuming processes, and propagation processes
that propagate information from the staging areas to designated destinations. Techniques
are also described for achieving exactly-once handling of sequence of items, where
the items are maintained in volatile memory. Techniques are also provided for recording
DDL operations, and for asynchronously performing operations based on the previously-performed
DDL operations.