Weird dog interaction!

[rbruck]

I adopted an 8 year old chow from the shelter about 3 weeks ago (previous owner died and family couldn't take care of her) and so far she's been great! Very outgoing and friendly with most people and was clearly well taken care of before.
I'm pretty good at reading dog body language and dealing with behavior issues from having an akita AND a gsd/pit mix that was probably the worlds most difficult dog but I'm totally puzzled at something. Took her for a long walk tonight and ran into some old guy with a dog in the park. The two sniffed each other politely and seemed to be alright and all of a sudden my dog plopped herself down in a sit position (kinda looked like how she sits in front of me when she expects me to brush her). The other dog sniffed her a few more times then started barking and kinda lunged when the other owner pulled him or her back. My dog barely reacted and when I started walking she didn't give the other dog a second glance.
So my question is what do you think the sitting down like that meant and why did it set off the other dog? I'm not sure if it was "submissive" behavior or "rude" I guess and I certainly never saw anything like that with my akita or gsd/pit. I couldn't see what was going on with my dogs tail when she was sitting but her general body language didn't look fearful or uncomfortable. Thoughts?

[Tippsy'smom]

Well, a LOT of other dogs don't like chows, weather it's the way the look(aggressive behavior things that are standard with chows like fur standing on end, tail up, stilted gait) or the way they smell(they don't smell like typical dogs). Sounds to me like it's more of the other dog just didn't like your chow.