Paul Graham, founder of startup incubator Y Combinator, recently made news in the tech world by warning young startups that they may have a harder time getting funding.

But a group of investors speaking at the Glimpse: Social Discovery conference on Tuesday cautioned entrepreneurs from reading too much into Facebook’s situation, noting that in the long road from founding to IPO, there’s plenty of room for smart social apps like Pinterest or Yelp to find success by replacing existing human patterns and interactions.

“The difference between behemoth Facebook and startups is huge,” said Jay Jamison, a partner at BlueRun Ventures, noting that it took Facebook eight years to get from its 2004 founding to its 2012 IPO.

“We’re looking for people creating companies today to be thinking about eight or nine years from now,” said Josh Elman, a principal at Greylock Partners.

What sets up a company to last eight years?

Investors agreed that the market for smart social apps isn’t totally saturated, pointing to services like Pinterest as examples of apps that replace existing human behavior — sharing photos of beautiful things with friends and admirers — that add to the user’s online experience, rather than necessarily replacing another service they already use.

“Some people will say that social is done,” Jamison said, bringing up the notion that Facebook, LinkedIn and Twitter have created “the big three” of social networking sites, with no room for others to join.

“I think that’s ridiculous,” Jamison said. “That’s like when, in the 80’s, we had three television networks. I believe the market in ten years will be saying, ‘There are hundreds of channels of social media tools compared to the big three we have today.’”

Elman said that for many people, LinkedIn is the way they create a resume and search for jobs, and Facebook is the way they share pictures of their kids and vacations with friends, behaviors that previously didn’t take place online.

So the message to startups looking for social success: find these types of offline behaviors, and create the online complement or substitute.

“If you can think about other human behaviors, you can think about networks and great ways to service those,” Elman said.

Disclosure: GigaOM is a sponsor of Glimpse: The Social Discovery conference.

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• Facebook’s IPO filing: ideas and implications
• GigaOM Euro 20: the European startups to watch
• Sector RoadMap: Social customer service in 2013