Currently I can't find any setting to have deleted tasks remain in the Toodledo web app after they are auto deleted in ToDo or 2Do. Does anyone know if this is possible with the Toodledo iphone app? (I don't want to re intall it just to check this). Either way I think this would be a great featrure so that deleted items don't clutter up the iphone apps but can be retained for reference on the web app. One work around is to use ToDo Notebook and convert the deleted tasks to a Note but then it still has to stay on the iphone app indefinitely.
I assume that deleted tasks in Todo (iPhone) are also deleted on Toodledo after a sync.
If you mean "completed" tasks, there is a synchronization setting in Todo to set how long you want to keep completed tasks on the iPhone. So you could set completed tasks to be removed from the iPhone immediately but they should remain in Toodledo according to whatever retention settings are in place.