(Reuters) - Viacom Inc's VIAB.O MTV network had its first summer of ratings growth in six years, the network told Reuters this week, a sign that the company is seeing progress wooing back coveted younger viewers who watch shows online.

Viacom is in the midst of a turnaround to improve declining ratings and ad revenue by focusing on six core networks, including MTV under its new Chief Executive Officer Bob Bakish.

Once known as the edgy network for cool kids, MTV lost its luster in recent years as the former Viacom management failed to invest in programming or a digital strategy.

In recent months, MTV has brought in new creative talent, re-engineered a number of existing shows and made an effort to reach a younger audience through social media, said Chris McCarthy, who was named president of MTV last year.

Turning MTV around is crucial for Viacom as it makes up about 15 percent of the company’s media network revenue, according to John Janedis, a Jefferies analyst. In the third quarter, media network revenue was $2.56 billion, 76 percent of Viacom’s $3.36 billion total revenue.

Summer is a key time for networks like MTV that cater to younger viewers because kids are home from school.

“The ratings trajectory is the best we have seen in several years,” Janedis said. “That being said, after the erosion of audience over the past six years, this needs to continue.”

During primetime, in its target audience aged 18 to 34 years, MTV saw a 31 percent ratings increase in August. The spike was helped by its new reality show “Siesta Key,” according to Nielsen data provided by Viacom.

From June through August, MTV saw the first three months of consecutive ratings improvement year over year in six years, the company said.

“Our original programming isn’t just about renewing for next season,” he said. “It’s about digging in and seeing what is working and what is not.”

For example, MTV made several changes to “The Challenge,” its reality game show featuring alumnae from its “Real World” and “Road Rules” shows.

MTV brought back some fan favorites of the show, upped the prize money to $1 million and quickened the show’s pace, McCarthy said.

The show’s ratings jumped 20 percent among 18-34 year olds, making it the highest rated season in over two years with that demographic, according to the Nielsen data.