In its latest monthly look at Windows Phone device statistics, AdDuplex reports that not much has changed: Windows Phone 8 continues to gain ground and Nokia continues to dominate the Windows Phone device market. But there are a few interesting tidbits, especially around Verizon and its selection of Windows Phone 8 devices.

The data again comes from mobile ad firm AdDuplex, which bills itself as the largest cross-promotion network for Windows Phone and Windows 8 apps empowering developers and publishers to promote their apps for free by helping each other.

Here are a few things that stand out to me.

Big picture, there are a few small changes. The top Windows Phone handsets worldwide are Nokia Lumia 800 (17 percent usage share), Lumia 710 (15 percent), Lumia 610 (15 percent), Lumia 920 (11 percent) and Lumia 820 (6 percent). The Lumia 610 and 820 (and its variants, like the Lumia 822) make a stronger showing this month.

But the big deal here, to me, is actually the 820. The thing is, the 820 is just one of three phones that are basically the same device, rebranded and modified slightly for different markets. When you combine the Lumia 820 with the essentially identical 822, you get 9 percent usage share, and since we can’t see the 810 in that chart, it’s possible that these devices are equal to, or nearly so, usage of the Lumia 920. That’s pretty amazing, and a nice indication that Nokia’s push to the midmarket (with the recently announced Lumia 720) is correct.

In fact, when you look at just the U.S., something really interesting emerges: The Lumia 822—on Verizon—is in the fact the number one phone in the country with 21 percent usage share. Filling out the top five are the Lumia 920 (18 percent), HTC Windows Phone 8X (9 percent), Lumia 710 (8 percent) and the HTC Radar (5 percent). When you combine 822, 810, and 820 usage, the figure is 29 percent.

Nokia still dominates other phone makers by a wide margin, but HTC has again made small gains mostly at the expense of Samsung and LG. Worldwide, Nokia controls 78.1 percent of Windows Phone usage, compared to much smaller showings for HTC (14.6 percent) and Samsung (5.6 percent).

In the U.S., Nokia still dominates, but less so: The firm controls 64 percent of Windows Phone usage, compared to a solid 26 percent for HTC and 9 percent for Samsung.

Windows Phone 8 usage grew to 31 percent, up from 26 percent the previous month. In the U.S., Windows Phone 8 represents 39 percent of Windows Phone usage. (This is usage share within total Windows Phone usage share, not total smart phone usage share.)

Finally, AT&T’s grip on the U.S. market for Windows Phone devices is apparently waning thanks to a strong showing from Verizon. The firm is still number one with 43 percent, but that’s down from 51 percent last month. Verizon surged into second place with 29 percent usage share (from third, with 16 percent). And T-Mobile fell into third place with 23 percent usage share (down from 27 percent). One can only wonder how well Verizon would perform if it ever got a version of the flagship Lumia 920 device. (And I’m curious what percentage of HTC 8X handsets are on Verizon.)

Finally, in the what-the-heck-it’s-fun department, AdDuplex this month reported on four new handsets it’s never seen before:

NOKIA RM-887_apac_prc_206 – most likely just a variant of Lumia 720 (RM-885)

NOKIA RM-860_nam_usa_100 – always on Verizon in the USA, with 1280x768 resolution

NOKIA RM-892_eu_euro1_016 – we’ve seen RM-892 in India before, but now we’ve seen it in Finland and we can confirm that it also has a 1280x768 screen (or at least a ScaleFactor of 160)

NOKIA RM-893_nam_tmous_201 – this is probably a T-Mobile variant of the phone above

Potentially some nice new Windows Phone 8 handsets to enjoy in 2013!