These days, if you had to list some of the fastest-growing online businesses, more likely than not one of the first names to pop into your mind would be LinkedIn (LNKD.DL). With a market cap of $26 billion, the company is nearly the size of General Mills. Yet on a revenue-only basis, the company is only 5% the size of the consumer goods giant. The reason for this disparity: growth. Over the past three years, LinkedIn's revenue exploded from $243 million to $972 million (a gain of 300%). But when management reports earnings on Thursday, Feb. 6, will LinkedIn prove that its growth can continue or will investors be sorely disappointed?

How high can you go?
For the quarter, analysts expect LinkedIn to report revenue of $438.28 million, 44% higher than the $303.62 million the company reported during the same quarter a year earlier. On an earnings-per-share basis, however, the bar has been set a lot lower. If analysts are correct in their assumptions, the company will report earnings of $0.38, just above the $0.35 it reported in the fourth quarter of 2012. But can management pull this off? If the past is any indication of the future, then the answer is likely yes.

Over the past three years, LinkedIn has grown its revenue considerably, but its earnings have also grown at a respectable rate. According to the company's most recent annual report, there have been two main drivers behind higher revenue: more registered users and higher revenue per registered user. Over this time frame, LinkedIn reported that its user base grew by 123%, from 90.4 million to 201.9 million. In that same time, it was able to increase the revenue per user by 79%, from $2.69 to $4.82.

These factors, working in concert, have helped push revenue higher, which has, in turn, improved the company's profitability. Between 2010 and 2012, the company's earnings rose by 171%, from $0.07 to $0.19. The disparity between the company's revenue growth and earnings growth can be chalked up to rising costs across the board.

But how does LinkedIn stack up to its peers?
While it's clear that LinkedIn has grown at a tremendous rate, it's hard to say how valuable the company is unless you compare it to its peer group. Chief among these peers are Facebook (META 2.33%) and Twitter (TWTR).

In terms of revenue growth, the high-flier is Twitter, hands down. Between 2010 and 2012, the company has generated revenue growth of more than 1,000% as sales have gone from $28.3 million to $316.9 million. Comparatively, Facebook's revenue has grown only 158%, from $1.97 billion to $5.09 billion.

When looking at profitability, though, the picture becomes a little clearer. Yes, Twitter has grown far faster than both LinkedIn and Facebook, but it has done so for two reasons. First, the company is far smaller, which means that its ability to grow should be greater, and second, the business has done so at the cost of its own profitability.

Over the past three years, Twitter's net loss has gone from $67.3 million to $79.4 million. LinkedIn, on the other hand, has seen its bottom line expand considerably. Over this time frame, the company's net income rose from a modest $3.4 million to $21.6 million.

As a percentage change, this is better than even Facebook, which saw its net income of $606 million decline by 95% to $32 million. However, this drop in profitability can be attributed to a ramp-up in research and development and selling, general, and administrative expenses. By the end of its 2013 fiscal year, this investment paid off for Facebook, as evidenced by the 55% jump in revenue it enjoyed and its hefty net income of $1.5 billion.

Foolish takeaway
Based on the data, it appears as though LinkedIn has had an amazing run these past few years. At some point in the future, this growth spurt will have to stop, but with online advertising approaching $1.3 trillion, it looks like the company has plenty of room to climb.

In the long run, it doesn't look like the company will prove to be a terrible investment, but with its shares trading at 134 times 2013's estimated earnings, it's slightly more expensive than the 102 times earnings that Facebook could be bought for. Either way, these multiples are extremely high, but an investment in Facebook would likely bring about less risk because of its size and profitability.