I’ve been getting dozens of e-mail invitations recently from people on a new social networking service called Spock. Then I started getting another batch of e-mails asking, “What the heck is Spock?” So I called the Spock team to find out.

Spock, I learned, is a relatively new combination search engine and social networking service. It’s optimized to allow you to find people on the Web. If you’re looking for your high-school sweetheart, or an attorney who works at a particular company, you can use Spock to find those people.

“Our goal is to make Spock.com the number-one place you think about when it comes to searching for people,” Spock co-founder Jay Bhatti said. (You can find out more about Bhatti on his Spock page.)

The big differentiator between Spock on the one hand, and services like LinkedIn and Facebook on the other, is that Spock crawls the Web looking for information about the people it indexes, while the other services depend on users inputting information about themselves, Bhatti said. Spock is primarily a search engine. “We search for everyone,” he said. “LinkedIn is a professional network, Facebook is a social network. What we are is search.” Spock currently has 250 million individual search results — that’s entries for 250 million people, Bhatti said. By comparison, the population of the United States is estimated at 303 million people.

Search on a person, and you’ll generally find links to their Facebook and LinkedIn profile, blog, and Flicker page, and other social-networking sites. For example, check out my Spock page.

Privacy Implications

In other words, if you’re on the Web, you’re probably on Spock, even if you never actually explicitly joined the service.

That presents potential privacy problems — what if you have a site on the Web that you’re trying to keep relatively quiet? Security-by-obscurity can be an effective way of ensuring privacy, if you use a pseudonym and don’t tell many people about it. Will Spock destroy that kind of privacy?

You don’t have to just sit by and wait for the Spock Web crawler to come to you. You can proactively join the service and build a “trust network” of your friends and associates. If you do that, you’ll get more relevant search results, says Bhatti. If you’re a member of Spock, and have a trust network, when you run a search, you can either search for top results on the whole Web — like on Google — or rank the results based on whether they’re in your trust network, or in the trust network of someone in your trust network.

That last feature — “personal search” — launched late in 2007, and that accounts for the surge in popularity for Spock, and why my e-mail box suddenly got filled with Spock invitations. People started running searches, uploading their address books, and inviting everyone they knew to join Spock. As is inevitable on social networks, some people limited their networks to people they actually know and trust, other people just went in looking to max out the biggest network possible, literally sending out 5,000 to 10,000 invitations every day. Spock is looking to throttle invitations to prevent trust from being devalued. “We’re saying trust should be very important, you shouldn’t trust everyone,” Bhatti said.

And if you join Spock, you can use it for some of the usual social-networking activity: Post your photo, describe yourself, and and invite your friends who are not on Spock to join. You also can watch what other people in your trust network have been doing on Spock (mostly, as far as I can see, updating their networks and descriptions — which is pretty much the only thing most people do on social mapping services like Facebook, LinkedIn, and Spock).

Tag, You’re It

You describe yourself using “tags.” My tags, for instance, include “Executive Editor InformationWeek.com,” “journalist,” and some of my current professional interests, including “Apple,” and “Second Life.” You can add tags yourself, or other people can add tags to your profile (you get to approve or deny tags you get from other people).

Spock suggests names of other people to put in your trust network, and I’ve found it’s fairly accurate. One out of every five to 10 names it suggests are actually people I know and trust enough to add to my network.

Spock is funded with $1 million in seed money it received in March 2006 from Clearstone Venture Partners, and a $7 million Series A round it received in December 2006 from Clearstone and Opus Capital. Prior to starting Spock, co-founder Bhatti worked at Microsoft in their management, server, and tools group, did some consulting, and attended business school at Wharton. Co-founder Jaideep Singh also is a Wharton grad, and was an early-stage venture capitalist at Clearstone. You can find out more about the management group at Spock by searching on “Spock team” at Spock.

Bhatti said he and Singh both come from an enterprise background, and found the transition to a consumer-facing service to be tricky. With an enterprise product, you take a long time developing it, polish the product and its marketing and sales pitch to a high gloss, and then take it on the road to a few customers. The sales cycle is long, and sales are high-touch — you spend a lot of time with each customer.

With a consumer-facing product, you develop fast, put it out for the public, and refine based on public feedback. And the public feedback is often voluminous — you get huge volumes of e-mail every day, which you have to learn to triage and prioritize — and plain-spoken and harsh. “If the consumer thinks your product sucks, they tell you,” Bhati said. “It’s a huge difference. You need a thicker skin.”

Grokking Spock

Why the name Spock? Well, obviously, it was the name of that dude on Star Trek, but when this service uses it, it stands for Single Point Of Contact by Keyword. The founders bought the domain Spock.com using $6,000 from their own pockets. “We were bidding against a lot of ambitious and excited Star Trek fans,” Bhatti said. But that name wasn’t their first choice. The first choice was Spoc.com, but that domain was unavailable.

Spock is a great idea. People-search is arguably the one practical application to the current social networking fad. Sure, playing Monopoly on Facebook is fun, as is posting updates on Twitter, but the one practical use for sites like Facebook and LinkedIn is finding people. I’ve done those kinds of searches on Facebook and LinkedIn with mixed results; Spock is looking to optimize itself for that kind of effort, and that’s potentially a very powerful tool to add to the Internet.

Of course, like many social networking services, it needs to achieve critical mass to start — it’s the classic Catch-22 of socnets, they can’t be comprehensive until they attract a lot of people, and they won’t attract a lot of people until they’re comprehensive. And the Spock team will have to execute well to deliver results.

What do you think? Do you grok Spock?