Thanks, DJD. Great job.
Uber statistical changes from June to July (Note: The stats from June are taken from the Official Server; also, the cutoff points I've chosen are fairly arbitrary - as of last month, the top 14 were "OU"):
General Usage:
1. Kyogre (=)
2. Groudon (=)
3. Rayquaza (+2)
4. Deoxys-f (=)
5. Palkia (+2)
6. Dialga (=)
7. Darkrai (-4)
8. Latios (+4)
9. Blissey (+2)
10. Lugia (+3)
11. Latias (-1)
12. Giratina (-4)
13. Mewtwo (-4)
14. Jirachi (=)
15. Mew (=)
16. Metagross (+1)
17. Forretress (+1)
18. Tyranitar (+6)
19. Ninjask (+22)
20. Garchomp (+8)
21. Bronzong (+16)
22. Heracross (+3)
23. Scizor (-7)
24. Deoxys-l (-3)
25. Heatran (+1)
26. Manaphy (-4)
27. Ho-oh (-8)
By my calculations, ubers "OU" may have grown from 14 to 15 pokemon. X-Act, when you calculate this, where do you cut it off? 1-15 represent 75% of all usages + a few hundred more out of more than 72000 total usages (~75.1% precisely, but I may have made a minor mistake of about 180 usages when tallying everything up). 1-14 represent ~73% of all usages. Do you round up or down?
For leads:
1. Darkrai (+1)
2. Deoxys-f (+1)
3. Dialga (+1)
4. Kyogre (-3)
5. Mew (+3)
6. Ninjask (+9)
7. Groudon (-2)
8. Lugia (+10)
9. Mewtwo (-3)
I have some skepticism regarding these numbers. There were nearly 3x the ubers matches on the smogon server this month than there were on the official server last month due to the release of the new server. I was out for a while this month, so it's possible I'm just missing something. I'll make what I can out of them.
General Usage
The metagame remains very offensive (although I've personally seen some very stallish matches recently) and SR is prevalent.
Rayquaza's risen to #3 - it must be the SD set. It's really caught on fire, and I believe it's responsible for most of the major changes this month. Over 50% of Rayquaza this month have run it, as opposed to the 35% that run DD (As a piece of advice to everyone running SD/ES/Outrage/EQ, you might want to try Jolly; I don't see any benefit to running Adamant). Palkia's risen to #5. Over 60% of this month's Palkia were Scarfers. People are catching on that Scarf Palkia is one of uber's best revenge killers (and one of the few ways to shut down all of the common Rayquaza variations). Darkrai's dropped to #7. Over half of Darkrais used are leads now. People believe that Darkrai can't do much else, apparently. Items are split fairly evenly between Leftovers, Choice Scarf, and Focus Sash. People are afraid of him being unable to set-up and sweep, so they're not carrying CM on him.
Giratina's drop is probably related to the increased use of dragon attacks this month. It just can't keep up with it. Considering the slugfests going on in ubers right now, Mewtwo probably dropped for a similar reason - it can't keep up with the heavy hitters - poor STAB, "poor" durability, no priority attack, no absurdly powerful attack, and long set-up time ("against what?"). Latios is far above Latias now - again, not too surprising. Lugia's risen quite a bit to fill the hole that Giratina left behind. Lugia should be able to stop most of the threats that gave Giratina trouble (I don't know how many people actually do this, but I've been in favor of dropping defensive EVs on Lugia and shifting them over to speed in order to outrun Jolly Ray and KO with Ice Beam). In response to the general rise of special attackers, Blissey usage has risen this month. Interestingly, Wish is nowhere to be seen in move usage. People don't know that it's legal on the smogon server.
Other than that, everything else is normal. Varied Kyogre types and support Groudon dominate the tier in an attempt to balance weather. Deoxys-f is widely used as a lead sasher or late-game LO sweeper. Dialga sets were fairly varied, although the mixed set dominated this month.
Come to think of it, if Giratina usage is so low, and relatively few Kyogres (20ish%) and Dialgas (25ish%) are used for Restalking, who is absorbing sleep on these teams? Also, was the Scizor usage drop just because of the new server, or is there another reason he wasn't used as much? Why are there several big jumps around the 20 area? I've heard of CBchomps but haven't seen one myself. I definitely haven't seen a T-tar or Bronzong. I've encountered a few Ninjask, but where did this huge surge come from?
Leads
I predicted last month that Darkrai would overtake Kyogre in leads, but I didn't anticipate Kyogre falling all the way to fourth. It makes sense considering the others counter it completely. I didn't expect it to change so quickly though. Mew rose this month, almost exclusively as a lead SRer. Most of them are similar to the suicide leads in OU atm, but these Mews have all their EVs pumped into their defenses and carry a Lum Berry for Darkrai instead. Most of them run a simple Hypnosis/Explosion/Taunt/SR set, but there are a few stray speed BPers in there who forgo exploding. IIRC, this set first appeared in June, but it's been gaining popularity. Ninjask jumped, probably to exploit the general lack of phazers atm. I have no idea where the Lugia jump came from or who's been using it as a lead. Did I miss something?