USA Business Visa Guide & Assessment:

B1 and B2 visitor visas are issued for persons travelling to the US for business activities. The B1 visa is the actual business visitor visa. The B2 visitor visa is a tourist or recreational visa. The B2 visitor for business visa is never issued without the B1 visa. Thus, if you still hold a valid B1 visa or the tourist visa, it can be used for planning a business trip.
If you are a citizen of countries which fall under the visa waiver scheme, and are visiting the United States for a time period of 3 months or even less, then you do not need to apply for a visa.
Activities like maintaining and running a business, gainful employment, being paid by an Organization which is in the US and professional sports and entertainment participation cannot be carried out under a business visitor visa. All these activities require a valid work permit to conduct. Still, there may be a very few strict possibility in which an individual may be granted permission for paid employment.

While on a B2 visa, you can however, carry out negotiations, request or discuss a purchase or investment, purchase and invest, participate in meetings, research, and hire staff.
In order for your business visitor B1 and B2 visa to be accepted, you will have to make it clear that the family and business ties back home are strong enough for you to return. In the event of inability to prove this, your visa application will be rejected.
If you are a resident of the countries a part of the Visa waiver program, then you can visit the US for a time period of 90 days without any visa.