Hi samkagan,
India's a huge country with a very long history, tons of population, and many different subcultures and castes.
Dosa are southern Indian.
I'm not from India nor do I have much exposure to their culture, but I do have a love for Indian food, and I'm lucky enough to live within walking distance of a Little India in my community. Actually I call it the ethnic village, because all within walking distance I have Latino, Chinese, Korean, Indian, Italian, and even Himalayan-Nepali mom and pop restaurants. Used to have a good Vietnamese restaurant there, but now you'd have to drive for that. Still, I'm truly blessed with a cornucopia of ethnic eateries practically in my backyard.
I discovered dosa for the first time at the Udipi Cafe restaurant.
There are photos of dosa on the yelp website reviews for the restaurant:
http://www.yelp.com/biz/udupi-cafe-cary-2
I liked the dosa and uthappam so much at my first exposure about 15 years ago that I wanted to emulate them at home. I set off on the internet for more info and recipes. Turns out they're made from roughly the same batter, but I suspect (don't know) that dosa batter's diluted down thinner that the uthappam batter. Dosas are more like an ultra crispy crepe, and uthappam's more like a pancake.
It calls for urad dal and rice soaked separately, ground and fermented with natural yeast (bacteria?) from the air. It takes several days and a lot of steps and effort, so I came to the conclusion that it wasn't happenin' in this kitchen. The biggest off-putter was that my Oster blender probably wouldn't be up to the task of grinding the grains and beans anyway, at least not for long before the motor burned out.
So I came up with a wheat flour/corn meal pancake and embellished it with finely chopped onion, tiny green peas, grated carrot and finely chopped jalapeno peppers for a very satisfactory Southern USA/Indian fusion version of Udipi's uthappam.
I really haven't attempted dosa. I do make crepes, which are eggier and more flexible than dosa.
Sadly when I went to Udipi last week for lunch the dosa was still good although smaller, but the filling wasn't as good. It was so watery it made the dosa soggy wherever it contacted it. Fortunately, it's customary to only put a small amount of filling in each dosa, so I ate the still crispy dosa and left the soggy part and the filling. Also over the years the spiciness has been tamed a lot. I guess even Indians who are at least 90% of the patronage at this establishment lose some of their taste for heat after eating our blander cuisine. I think I could even take my capsaicin averse husband to Udipi now.
I filled up mostly on idly and sambar, and the lovely ripe watermelon they had on the cold bar. If I can even find watermelon this time of year in local markets it's very expensive, so I definitely got my money's worth. The papadums were excellent too; thin, crispy, bubbled up loveliness. It's $8.99 plus 70 cents tax for the weekday lunch buffet. It used to be better, but it's still very okay. Almost everyone drinks water, so that's not an added expense. The water is refilled so religiously and all the staff are so pleasant, I couldn't help but tip 20% anyway even though it's a buffet. I also noticed that the staff is much more familiar with English than they were in the past.
It was very interesting to spy on the adjacent table's two Indian mens' conversation. They were (probably H1B visa) programmers. They talked about food. One ate meat, the other not. The one that didn't related an experience on July 4th shortly after coming to USA where his host asked him if he wanted a hamburger, and he agreed. Then he saw the red "squishy" patty, and reneged. He'd never seen raw meat before. He'd only seen it cooked, I'd hazard a guess, maybe in commercials.
The same no-meat guy, who seemed very engaging and talkative, went on to describe his experience coming back here from a visit to India. He said it seemed like an apocalypse had happened, and how lonely it felt to just see buildings and cars but no people on the streets. Pretty fascinating to me, since I'm crowd phobic to the max. Of course this whole time, I've got my nose in "The Girl with the Dragon Tattoo," so they spoke freely. 
The uthappam were small inferior shadows of themselves with NO vegetables baked/grilled into one surface like my previous experiences. I'm so glad I got some better ones years ago that inspired a dish I have made a hundred times, and everyone who eats them loves.
I too would be very appreciative of any information any member could give on dosa making and uthappam. I sure would like to be able to make them at home with the equipment I have. I have Googled away for years, but it just doesn't seem to be a thing that's very easy to do in a Western kitchen without importing specialized equipment from India. These recipes are thousands of years old, though, so I'm sure they didn't have these electric grinding machines back then.
I'm hopeful that someone who's experienced in dosa making can educate us Westerners.