Glam Media, a collection of highly curated blogs mainly centered around fashion, beauty and health, is acquiring Ning, the social media platform co-founded by Marc Andreessen.

Andreessen is joining Glam Media's board of directors.

As consumer behavior broadly moves from old media to the web ... the opportunity for high-end online content is gigantic and our combined company will be in the pole position in this huge market, Andreessen, who also is the chairman of Ning, wrote in a post on his personal blog.

The combined companies will have over 240 million users and 100,000 publishers.

Ning is a custom platform for social media networks used by individuals and professional content creators to build out and manage websites that can integrate with Facebook, Twitter and Google Inc's social network Google+.

Social is not only creating large consumer networks, social is also transforming other industries, said Samir Arora, chairman and chief executive of Glam Media, who ticked off LinkedIn Corp for online recruitment and Zynga for gaming as examples. No one has really cracked the code for content and media.

With Ning, Arora said Glam Media's network of more than 4,000 authors and 2,500 publishers will now have access to an integrated social platform.

Ning was founded in 2004 by Andreessen and Gina Bianchini. About 18 months ago, under the direction of Ning Chief Executive Jason Rosenthal, Ning changed to a subscription-only model from a hybrid that depended both on subscription and advertising revenue.

Monthly subscriptions to Ning run anywhere from $2.95 to $60 a month, Rosenthal said. He added that Ning was attracted to Glam Media's advertising platform.

It's two different sides of the same coin, Rosenthal said.

Rosenthal is joining Glam Media as executive vice president social media and general manager of Ning.

The Glam board directors that Andreessen joins include Accel's Thereisa Ranzetta; Draper Fisher Jurvetson's Tim Draper; Glam Media co-founder Fernando Ruarte; Hubert Burda Media's Marcel Reichart and Glam Media Chairman Arora.

The terms of the deal, expected to close in the fourth quarter, were not disclosed.

(Reporting by Jennifer Saba in New York; and Andre Grenon)