Marc Andreessen, the co founder of Netscape and one of Silicon Valley's best known VCs had some praise for Yahoo's new CEO Marissa Mayer.

“I’m super happy for Marissa,” Andreessen said on stage at the Fortune Brainstorm Tech conference in Aspen, noting that it clearly marked a pivot in Yahoo’s strategy from a focus on media or ad sales to a focus on tech products.

“It’s a big job she’s stepping into,” Andreessen said. “A big commitment. A big challenge.”

He added that the challenge was comparable to what Steve Jobs faced when he returned to Apple in 1997.

“Apple showed that tech companies can be turned around,” Andreessen said. But “there have been very few web turnarounds” — and very few CEOs of Jobs’ caliber, he added.

Mayer, by contrast, has never held a C-suite job before. “There’s a lot of work to do,” she said in a statement to the Fortune conference organizers.