The B visa is an important tool in the U.S. immigration law belt, and it can also be a bit confusing because of it's multi-faceted nature. The B visa can be used by tourists who just want to travel to the U.S. for a little while; and it can also be used by business professionals who are engaging in business activities in the U.S.
If you are a business professional entering the country on business, the B-1 visa is the one you are looking for. If you are a tourist just looking to see the sights and sounds of America, then the B-2 visa is what you will need.
However, it is important to realize that whether you get a B-1 or B-2 visa, you need to act in accordance with the law while you are in the U.S. Illegal or illegitimate activities that are performed by people who are on a B visa while they are on the U.S. can lead to numerous consequences, including the inability to return to the U.S. for an extended period, or even permanently.
There is also a long list of requirements that a B visa applicant must meet before they are able to qualify for a B visa.
Though, if you can't get a visa, there are pilot programs that could allow an individual to enter the U.S. without one -- though the requirements and abilities granted by such a pilot program can be complex. Be careful with this visa and make sure you understand the rules before you proceed.
Source: FindLaw, "To B or Not to B: When B Non-immigrant Visas Are Appropriate," Accessed June 4, 2015