Try actually reading the thread
"Basically, in this experimental tier, named "OU (no Mega)", we're going to test the effects of mega evolutions on the metagame in order to address, among other things, the following issues:
1) bearing of mega evolutions on the match up component of the game;
2) restrictions on team building caused by mega evolutions;
3) level of diversity in a metagame without mega evolutions.
The OU (no Mega) ladder, which is being implemented as I type this post, will be open for playtesting for a few weeks. The tier will basically follow the standard OU banlist and rules, with the only exception that mega stones will have no effects. After we get a stable metagame, and according to the level of interest (or lack thereof) it creates in the playerbase, we might start to progressively introduce the mega evolutions that we, as a community, perceive as balanced for the tier."
