[moe]

MongoDB now has a per-database write lock and will have a per-collection write lock in the next version.

That doesn't help when you need to make a bulk-update on a busy collection. Busy collections have a tendency towards being in need for bulk updates occasionally.

At the very least provide links that aren't nearly 2 years old.

The first link is 1 month old.

The other links also still describe the state of the art. Feel free to correct them factually if that is not true.