i have tested about 20 traffic sources, and this is my observation of what are the most profitable.
1. traffic source with less competition
a. small traffic source less bidders
b. focused on desktop(other) traffic therefore mobile less bidders
c. geo has few bidders, other bidders focused on other geos
d. within the same geo bidders are promoting different verticals, so less competition for the SAME app
2. lower bid price (as a result of less competition), cheaper and lower cost for same traffic
3. more targeting options like browser OS ISP, able to exclude unprofitable segments
4. interface harder to use/tougher tracking etc - less bidders are willing to adjust and so less competition
5. more placements more traffic and therefore higher chances to find a group of profitable placements.
Looks like you putting quite some effort into mobile, that's the way to go mate!
Keep sharing the good stuff and more important don't stop testing.
List them with matching analysys
Okay one question how or from where do you find new traffic sources ?
1. Search stm
2. Ask your mastermind group
3. Search Google and click through every link in the first 5 pages and every link from each page.
You're doing it right! Lots of good info in the #1 part