Though LinkedIn (LNKD.DL)is by no means the largest position for professional asset management firm Churchill Management, the stock made up 1.46% of its portfolio as of the most recent 13F filing. Churchill definitely liked what it saw in the professional networking giant last quarter when it acquired nearly 167,000 shares, the large majority of its current 171,000 share position. That brings its total stake in the company to approximately $44.4 million as of this writing.

So, what is it about LinkedIn that warrants so much optimism? The good news for investors, and likely a reason money managers like Churchill have gotten onboard the LinkedIn train, is that there are a number of positives leading up to its first quarter earnings announcement on April 30th. Naturally, there are challenges as well, but the strong management team led by CEO Jeff Wiener, a definitive business plan, and signs it is executing on that plan bode well for shareholders.

What's not to like?
Of the three operating divisions at LinkedIn, its talent solutions -- the unit focused on jobs -- is far and away its primary driver of revenue. Last quarter, the talent unit enjoyed a 41% year-over-year jump in revenue, posting an impressive $369 million in sales -- that represents 57% of the top line. However, talent revenues made up 61% of sales in the previous quarter, so LinkedIn is doing a better job of "spreading the wealth."

The continued diversification of revenue across the multiple divisions is a key area for investors to monitor going forward, including the first quarter earnings announcement next week. Why? It is rarely a good idea to be overly reliant on any one aspect of a business, which is one reason Weiner and his team are focused on growing the other divisions.

And it is working.

On a percentage basis, the marketing solutions unit saw the largest revenue increase of the fourth quarter, growing an impressive 56% year-over-year to $153 million. Marketing sales now make up 24% of the top line, up from 19% the previous quarter.

The final piece to the LinkedIn revenue puzzle is its premium subscription unit, which made up a "mere" 19% of revenues. However, the unit grew 38% year-over-year, contributing $121 million in sales.

As LinkedIn continues to post strong sales each quarter, its impressive member growth sometimes flies under the radar. But as last quarter demonstrated, despite being more of a niche player in the social media universe, LinkedIn grew to about 350 million active members in the fourth quarter, up 9% from 332 million the prior quarter.

To put that into perspective, Twitter increased its monthly average users an anemic four million over the same period, growth of just 1.4%. Twitter is not nearly the specialized networking solution that LinkedIn has become, so it should have a much broader appeal. Granted, Twitter also revamped its processes for determining what is, and is not, an MAU last quarter. Still, the notion that LinkedIn is blowing the member-MAU doors off the widely discussed, but less utilized services of Twitter, is impressive.

A possible bump in the road
One area LinkedIn investors -- including big time money managers like Churchill -- would be wise to monitor is its overhead. Last year, costs jumped nearly 50% to $2.2 billion. According to CFO Steve Sordello, shareholders can expect more of the same this year. Assimilating new acquisitions like ad solutions provider Bizo and hiring additional sales people, not to mention the recent $1.5 billion deal to buy career educational service provider, will keep LinkedIn expenses on the rise.

That said, strong revenue growth -- and the steps taken to further diversify not only revenues but also services, including content creation and international expansion -- are compelling reasons why LinkedIn has earned consensus "strong buy" recommendations from Wall Street analysts. Those factors likely drove Churchill Management to increase its ownership so dramatically the past few months. Investors in search of long-term growth should consider doing the same.