After LinkedIn (NYSE:LNKD) announced recent Q4 and year-end earnings, it's hard to imagine anything raining on its parade right now. Shareholders, after enjoying a 25% jump in share prices since the Nov. 7 earnings news, are going to feel giddy for some time, too.

The recent announcement that there's a new professional networking alternative in town won't send LinkedIn aficionados running for the exits, nor should it. At the same time, LinkedIn CEO Jeff Weiner is too good to ignore a potential threat simply because of its size, or newness to the market.

Who are these guys?
All three of LinkedIn's business units -- Talent Solutions, Marketing Solutions, and Premium Subscriptions -- performed admirably in Q4. Weiner's efforts to ensure LinkedIn has several viable revenue streams speaks to his leadership acumen and is a key reason LinkedIn's share price has done as well as it has.

LinkedIn already faces competition from the likes of Facebook (NASDAQ:FB) and its relatively new jobs app, not to mention the potential of its billion active users. With that many active visitors, Facebook can take its desires to expand revenues in any number of directions, including getting serious about the professional networking market. Which is more a matter of if, not when, for the social media giant.

Google's (NASDAQ:GOOGL) Google+ service is seen as more of a threat to Facebook than a viable competitor to LinkedIn. After all, Google+ began last year as a social-networking alternative, and according to a recent report, it already boasts more than 300 million active users. But like Facebook, its sheer size and track record of going big into new markets makes Google another threat to Weiner and the LinkedIn team.

Even with pressure coming from industry heavyweights like Facebook and Google, you can bet Weiner is doing his due diligence on the new professional networking service introduced today, called Relationship Science. Why? A couple of reasons. First, it's always a good idea to keep an ear to ground as it relates to changes in the marketplace. That's what good companies like LinkedIn -- and good CEOs like Wiener -- do.

Another reason LinkedIn should take note of privately held RelSci is where its $60 million in funding came from. Billionaires Kenneth Langone -- one of the original co-founders of Home Depot -- and Henry Kravis of KKR fame are two of the big hitters. Capital IQ's Neal Goldman (founder of RelSci) and Hearst are also intimately involved in the new LinkedIn alternative.

What's the diff?
The idea behind the new RelSci professional networking service is to map users' relationships with more than 2 million business people around the globe, in the hopes of closing deals, securing jobs, and other professional networking benefits. What's different about RelSci is that unlike LinkedIn -- or Facebook and Google+, for that matter -- it doesn't require that contacts are "enrolled" to show up in search results, nor does it rely on users to input data. Rather, RelSci scours the Internet using a search function, digging up relevant connections for users based on their search criteria.

At $16.6 billion in market cap, and more than 200 million active professional networking users, LinkedIn isn't quaking in its boots with the introduction of RelSci, or its impressive financial backers. But what Weiner and the team need to recognize is that RelSci is just the latest new effort to home in on LinkedIn's impressive market. More will come.

RelSci may not be a concern right now, but it is a peek into what LinkedIn can expect in the future. That's what success does -- it breeds competition.

Fool contributor Tim Brugger has no position in any stocks mentioned. The Motley Fool recommends and owns shares of Facebook, Google, and LinkedIn. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.