The Kardashian family phenomenon

The sisters have created an empire despite their lack of traditional talents that lead to stardom. And it's not all sex appeal and scandal -- their tight-knit family seems to be part of the draw.

When a reality show about the Kardashian sisters of Calabasas debuted in fall 2007, most people had never heard of the family and what was known could scarcely be considered positive.

Their late father, a lawyer, helped O.J. Simpson win acquittal at his murder trial; middle daughter Kim palled around nightclubs with Paris Hilton; and a graphic sex tape featuring the brunet and a former boyfriend ended up in the hands of a porn distributor.

Two and a half years later, the Kardashians are an inescapable cultural and commercial force. Their series, "Keeping Up With the Kardashians," which concludes its fourth season Sunday on E, has shattered viewership records for the cable network and spawned a spin-off show. Kim Kardashian.com is the world's most popular official celebrity website, according to its operator. Checkout-aisle magazines and gossip blogs cover the smallest details of the sisters' lives. And Madison Avenue calls on the family to sell mainstream America everything, from diet pills and orange juice to NASCAR and fast food.

Their popularity comes despite the fact that the sisters lack the talents that traditionally lead to superstardom and, some believe, partly because of it.

"There's an aspirational quality to somebody who has become a celebrity for -- and I don't say this in an offensive way -- but for not doing anything celebrity-worthy," said Matt Delzell, an executive at Davie Brown Entertainment, a company that helps corporations choose celebrity endorsers. The young women to whom the Kardashians appeal, he said, "tend to think that's pretty cool. That's something I might be able to achieve."

Television programming, especially on cable, is increasingly dependent on created rather than established celebrities. Turning nobodies -- or virtual nobodies -- into reality stars is cheaper than hiring actual somebodies. But the Kardashians have transcended that level. While personalities on Bravo's "Real Housewives" franchises and MTV's "Jersey Shore" and "The Hills" seem to exist to promote those shows, the Kardashians have turned their program into a promotional vehicle to expand their own empire.

Kris Jenner, the family matriarch and self-described "momager," said she had little time for those who criticized her brood for being "famous for nothing." She is too busy sorting through business opportunities, working on "SPINdustry" -- a Kardashian documentary special debuting Sunday on E -- and generally protecting what she only slightly self-consciously refers to as "our brand."