We recently came across an issue in salesforce.com, that even though tasks are set to Private, individuals will still be able to see the tasks, as long as the Accounts and Contacts are set to Public through the Security Settings.
Upon searching, there is actually an idea in salesforce ideas that notes this as an open issue.
For this client, what we did was create a couple of visualforce inserts that use the role heirarchy and sharing settings to show and hide activities based upon their role. Have a look below!
If you’d like to enable truly private tasks and activities, contact us–we’re happy to help!
