Unrealistic expectations may be a bigger issue for people who invest through crowdfunding rather than fraud, Steven Dresner, founder of DealFlow Media in Woodbury, New York, which is a research and database firm that tracks equity-linked offerings.

"There'll be far more instances where people invest in a crowdfunded project and then realize that it's really hard to make a profit," Dresner said.

Less than half, or 45 percent, of businesses founded in 2004 were still around five years later, according to a 2011 study by the Kauffman Foundation, a nonprofit dedicated to entrepreneurship.

Investors should make sure they receive disclosures about how shares are priced and any updates such as management changes between the time of their pledge and the closing of a crowdfunding deal, Dresner said. They also should understand the rules around canceling a commitment, said Dresner. Those details may be worked out in the SEC rulemaking, he said.

The law also lifts a ban on the marketing of private offerings to the general public.

In the past, securities laws generally required firms to market non-publicly traded securities only to so-called accredited investors with whom they've had an existing relationship. That generally means individuals with assets of greater than $1 million, excluding a primary residence, or those earning more than $200,000 annually. The solicitation rules were designed to protect the average investor from deals with less disclosure and higher risks.

'Blanket the World'

While firms can now market to anyone, they still must sell private offerings only to accredited investors, said Mercer Bullard, an associate professor of law at the University of Mississippi. That distinction will be difficult for regulators to enforce.

"If you're a fraudster you just blanket the world with solicitations," said Bullard, who's also founder of the investor advocacy group Fund Democracy. "As soon as the money comes in from non-accredited investors you collect it and shut down your operation as soon as any heat is brought to bear."

People living in wealthier retirement communities can expect to start receiving solicitations to invest in private offerings as a result of the law, said Roper of the Consumer Federation. "They should treat them exactly like they treat the rest of the junk mail they receive," said Roper. "Throw them right into the trash can."