From: wikien-l-bounces@Wikipedia.org [mailto:wikien-l-bounces@Wikipedia.org] On Behalf Of Brian Haws
On at the least the narrow point of deleting things off of your own talk page, I see it done fairly often, admins and non-admins alike. It's not a blockable offense is it?
It seems clear that the community expectation is that user pages are the user's own property and users can delete as they see fit. If you delete messages sent to you by others, then it is a reasonable assumption that you have either read the message and no longer wish to see it, or for some reason you don't want it on your talk page - perhaps it's vandalism, spam or abusive. Either way, the message remains in the edit history and though it may be inconvenient for a third party trying to sort out who said what to whom, it can be done.
Even if it's something reasonably official, such as a notification of RFAr or RFC proceedings, then it might be considered the same as service of a summons. The recipient might immediately tear it up and throw it away unread, but the summons has been served and there is an official record of service. We can send someone a message, but we cannot force them to read it.
As has already been noted, it is easy to find examples of every sort of behaviour. Some editors seem to never clear out their talk pages, others do it frequently and obsessively. Perhaps this reflects the editor's personal attitude to housecleaning and clutter rather than any considered adherence to official policy!
-- Peter (Skyring)