About 200 years ago a gang of regular mumsnetters decided they wanted to just hang out with the cool kids and set up another forum which was by invitation only.
Lots of hurt feelings are people were either not invited who thought we in with the cool kids or who were vetoed by some of the coolest kids (not exactly sure how it worked).
Some people were genuinely upset by it as people they thought they were "friendly" with online turned out to be not so friendly after all.
Not sure if there arestill some threads knocking around about it.