Museums are changing. Gone are the days of wealthy connoisseurs opening exhibits with private collections of rare treasures. Now, it's about an idea, a niche, fundraising and marketing. Uniqueness is no longer the ultimate goal; it's the everyday, a narrative woven through unremarkable relics to tell the story of a specific group's experience.

The number of heritage museums dedicated to portraying the history and culture of a given group of people has surged in the last 30 years, according to Schroeder Cherry, counselor to the director of the federal Institute of Museum and Library Services, which provides grants for African-American and American Indian heritage museums.

Cherry attributed the increase to a more educated society and the lack of "significant" minority coverage in mainstream history museums.

"I think it's about preserving legacy," he said. "There's a difference between having a museum with a story told of and by its own people and a larger museum with the story as a subset."

Museum founders are also responding to the market; African-American tourist spending alone has reached about $40 million annually, according to Angela daSilva, president of the National Black Tourism Network. The number of black museums across the country currently in operation lies somewhere between 300 and 500, according to the Association of African American Museums.

DaSilva explained that the topics explored in black museums resonate with many African-Americans because of today's racial climate, resulting in a huge increase in black history-related tourism.

"It's culturally driven," she said. "I think that a lot of what's going on in the country today - for instance, the nooses that are suddenly everywhere - drive home the point that this is still not over."

David Terry, executive director of the Reginald F. Lewis Museum of Maryland African-American History and Culture in Baltimore, attributed the increased popularity of heritage museums over the last 20 years to an "information revolution" that has changed the study of history itself.

"This is very much in line with a larger trend that people were beginning to attempt to understand history from the inside out, from the perspective of the lower classes economically, from the perspective of non-white males, from the perspective of grass-roots political groups," he said. "I like to say to folks, in many ways our institution is a product of the history that we portray."

The Smithsonian Institution - which opened its National Museum of the American Indian in September 2004 - continues to ride the wave of interest in niche museums by moving forward with plans for its newest addition to the National Mall: the National Museum of African American History and Culture.

But the Smithsonian has encountered a number of challenges in its attempts to combine its big name with a niche market. Some early supporters of establishing a national African-American museum, for instance, objected to attaching the museum to an institution they felt had ignored African-American history and heritage for the majority of its existence.

When Congress passed legislation authorizing the museum in 2003, a new debate arose over its proposed location; many African-Americans felt putting the museum in the Smithsonian's existing Arts and Industries building would be the equivalent of accepting a white "hand-me-down" and would restrict exhibit space. The only other site on the National Mall - the preferred venue for Washington museums because of its prestige and prime location between the Capitol and the Washington Monument - had recently been included in a "reserve area" created by a congressional bill restricting development on the Mall.

That site was eventually approved for the planned African-American museum in 2006, after it was determined that the restriction did not apply to the museum because legislation to establish it had already been introduced. The museum is expected to open on that site in 2015.

Similar concerns were raised when the Lewis museum, which opened in June of 2005, was still in its planning stages. Supporters quickly rejected the suggestion that the museum be housed in the defunct Baltimore City Life Museums, opting to construct a new building on a prominent corner site rather than take "leftover seconds."

In fact, Baltimore's early efforts to establish the Lewis museum, the largest African-American museum on the East Coast and the second-largest in the nation after Detroit's Charles H. Wright Museum of African American History, foreshadowed the Smithsonian's current project in more ways than one.

Neither of the museums started with a large private collection, an obstacle common to many black museums; the dearth of preserved artifacts and documents both propels people to create museums to honor an overlooked heritage and makes it hard for them to do so.

Terry says the best advice he can give to the NMAAHC's founders and curators is to be authentic and responsible when planning exhibits.

"No museum can be everything to all people," he said. "Don't get stuck trying to meet people's expectations."

Vernon Courtney, president of the Association of African American Museums, noted that a museum can never capture the diversity of an entire ethnic group, but neither should it try to. "There is no 'the' African-American experience in America," he said. "We all have a host of experiences."'

Terry, who advocates creation of more heritage institutions to add dimension to the story of a group's common experiences, acknowledged that black museums have struggled to attract blacks and whites in the past, but he believes "today's museum-going public is much more sophisticated."

One hurdle in attracting visitors to a museum documenting the American experience of a marginalized group is the question of how to treat sensitive issues in a way that is provocative and moving without being divisive or inciting resentment.

Terry acknowledged that the placement of some African-American museums makes them "like the apartheid museum in South Africa, or a Holocaust museum in Germany," but emphasized if anything, it only makes them more important.

Above all, he said, tell the truth. "If you don't go after a complicated topic truthfully, whether or not you've offended somebody is beside the point, because you've sidestepped it," he said. "Our museum deals with slavery in many ways but we keep it in context; slavery is presented in our exhibition as sort of a prism for understanding how we have been related and connected to other Americans, but also as the laboratory, if you will, for how we developed many of our 'American' traits.

"We want to avoid looking at slavery as something without use or as an anomaly," he added. "Slavery was an integral part of how Africans lived, and we treat it as such." As for whether a niche museum documenting only one part of American society is in any way separatist or "un-American," Terry dismissed the notion.

"I think the melting pot analogy has been, at least by my understanding, sort of corrected. More like a salad. America is the sum of its parts, and you have to understand its parts before you can understand the whole thing."