Where we can we find SMB in USA and India? I mean, a lot of marketplace (like Amazon) have small business which sell goods on it. Where we, as a startup, can find this small business? May be any site, forums or other channel?
What sort of SMBs are you looking for? There are over 5.68m SMBs in the US and you would be hard pressed to find a public list of each one.
However, if you know a location and/or an industry, you can start with a place like hoovers.com or yellowpages.com.
Hope this helps! Let me know if you have any more questions about list building, it's one of the most important steps in any sales process.
Tell me more about what you are looking for. I'm not positive I understand your question - but if you are looking for a way to TARGET those SMBs with ads and gain them as customers, then this is my answer:
We had a TON of luck by targeting them on facebook ads. Depending on your budget - there are millions of them in USA alone. The targeting option that we set in the facebook ads platform was "Small Business Owners". It was one of the key ingredients to growing our SaaS application almost 400% this year.