On several occasions I've attempted to come back to an idea I had annotated (or was just following the discussion on) only to find the idea missing. The sense of loss is a bit eerie, made all the more so because the Halfbakery isn't particularly conducive to meta-discussion (e.g. "Hey, what happened to that one idea that was there earlier today?"). I'm forced to simply accept the loss and move on without asking questions, leaving me feeling a bit like a North Korean whose co- worker has just disappeared without a trace.
I propose then a protocol for deleting ideas that addresses this issue, but requires no modification to the Halfbakery software itself. Instead of deleting ideas immediately, first delete all of the annotations, and blank the description text. Replace the summary line with something along the lines of "Deleted by [username] because xxx" (I assume here that moderators can change an idea's text rather than simply delete the idea). Finally, append [deleted] to the idea name. No further annotations should discuss the idea substantively (and those that attempt to should be deleted), but discussions of the deletion and the reasons for the deletion are acceptable.
The original poster is expected to cull soft deleted ideas after a reasonable period of time has passed; long enough that everyone who was involved in the discussion has had a chance to be made aware of the development, but not so long that deleted ideas hang around cluttering things up unduly.-- ytk, Jun 08 2012 I don't think I have ever been unable to find an idea in this way - the only ideas that have gone pfffffftttt are the ideas that I expected to go that way.-- po, Jun 08 2012 random, halfbakery