1 answer
I dont think trigger will be executed when the record is shared. For each object there is a share table.You could write a batch job to get the records from sharetable based on lastmodifieddate and send out email to the user. you can schedule the batch to run hourly or daily.http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_bulk_sharing_creating_with_apex.htm