Kudos to CEO Gregg Brockway and the other folks at TripIt, that handy online travel tool that makes keeping track of travel a less formidable task. It’s satisfying to see a smart, well-executed site succeed, especially to the tune of up to $120 million.

As I followed the excitement pouring forth online yesterday about the deal, I couldn’t help but think: Is it time for travel start-ups launched four or five years ago to finally achieve success after being waylaid by the recession and continuing economic malaise, or are we simply in the consolidation and elimination phase?

When I started my previous position as editorial director at TravelMuse in 2007, online travel planning, research and organizing was the new frontier, a vast landscape just waiting for the right concepts, engineers and venture capital to come along. And come they did.

Around the time TripIt, TravelMuse and UpTake launched, the space quickly grew to also include NileGuide, GoPlanit, RealTravel, Tripbase, TripWolf, TripHub, TripWiser, Triporati, Tripology, OpenTravel, WholeTravel … you get the picture. I’m sure I’m leaving out a dozen other quasi-competitors (some who even partnered) from that era, if not more.

At least one didn’t make it past 2008; a few sites still seemingly active have declining traffic and lack noticeable updates. On a positive note, Rand McNally acquired Tripology in late 2009, UpTake—arguably the traffic leader—purchased RealTravel in November, while TravelMuse became part of the Travel Ad Network, and all are still up and running.

These three acquisitions didn’t involve nearly the same kind of wow money that TripIt attracted, but they were exciting in the sense that companies were partnering to better utilize resources and focus on their combined strengths.

But back to my question: Where’s the space headed for everyone else?

New and improved competitors are entering the market (WanderFly, for one), and with travel making a comeback this year—led by the return of business travel—owners of early trip-planning sites likely hope to register growth and make up for the recent lag years.

Could they get left behind, though, because of unlucky timing? Just as travel is making a recovery, the buzz is around mobile and apps and how that’s where it’s at for new content research and organization of travel plans.

But many first-generation trip-planning sites have tight budgets, and the field is still crowded. Is there enough investment money left to improve current products and create new app tools for these sites to distinguish themselves, as TripIt did, and survive? Or is it too late for some of these early players? I’d love to hear your thoughts.