Alas, Poor Club Kinki, I knew It Well...
There's a land rush on; people are tearing stuff down and selling lots and occasionally, whole sims. Changing things is pretty much a constant, and isn't going to slow down - even once the big names have come along and totally bought up the mainland for vast sums of cash, they will continually chop and change what they've got, just as they fiddle around all the time with their corporate websites - so my suggestion isn't just for now, it's for always.
Unlike the web, SL is still a work in progress, unencumbered by ossified RFC's and irrelevant standards. This gives us a chance to make genuinely useful features which have no workable equivalent on the 2D web - and what I want is, back-tracing or pinging of landmarks.
Club Kinki is my case in point: it had a high(ish) level of traffic and I'd pop over there every so often. Then it went into "landmark invalid" state, during a buggy period, so I just assumed the sim had crashed whenever I tried it. Then, one day, the LM worked again - and I found myself in the middle of the NBC corporate plaza in SL, surrounded by Mies van der Rohe office blocks (I know; go figure...).
I suspect NBC didn't know about Club Kinki - but more to the point, all those with LMs to Club Kinki didn't know about NBC. I want a feature that allows LMs to be marked as "invalid", so that an attempt to TP to a location made invalid by changes of ownership, use, buildings etc will bring up a prompt saying "This LM is no longer correct - search for name/delete/cancel", so that over time, people naturally self-prune their landmarks and stop trying to go places that no longer exist. The new builder of the space, or the old owner when they sell the space, can tick an option that says "any LMs in this area should be revoked/marked invalid".
Think of it as the memorial that Club Kinki really, truly deserves...