Parcel Crash

1. I've heard of sim crashes, but not parcel crashes. Are they the same thing?

2. If so, what happens when a parcel or sim crashes? Do all the objects on the land get returned to the owner's inv... or do the objects just disappear?

1. Parcels cant crash, only sims (and the whole grid )
2. No, the objects stays on the land. However very rarely they will do a rollback, then you might find your recently placed objects lost. What happens when a sim goes down is that it apperes pink on the map for a few minutes (well, it can be longer, but then its a bug) and you cant go there. Its a bit like when a webpage goes down, the content is still there, its just not on reachable on the web.

OK, so once your object is put on your own land, it's permanently and safely "saved" there even if the sim crashes?

Not by any means. I recently changed a value in the Estate Tools for the sim I own, and most of the buildings and objects I had spend a week putting in place disappeared!! Some came to my Lost and Found folder, but others seemed lost forever, until I found that coalesce trick.

Rock

You prob changed the settings for build then? To only group builds? And everything where you didnt have your tag on when putting out was returned.

Well in theory it is. Bugs happen though, and so does rollbacks. But yes, it is pretty safe.