Stay on Top of Enterprise Technology Trends Get updates impacting your industry from our GigaOm Research Community

What is the thread that ties together the rapid rise of companies as different as Facebook, Zynga, Twitter, The Huffington Post (s aol) and Quora? Wedbush Securities, a brokerage firm that analyzes the valuations of private companies, says they are all players in what it calls the “Second Internet.” Wedbush says there are certain attributes that allow such players to grow and thrive while more traditional players — including some of the leaders from the early days of the Internet — fail to prosper and gradually recede into history. The most important of these attributes, the firm says, is an understanding of the value of the social web.

The social nature of this new wave of Internet companies is such a major factor that Wedbush also calls it the rise of the “Social Internet” in a new report on the sector, and says successful companies are powered by similar features, including:

Platforms open their API to developers

Continuous and rapid pace of innovation (see Facebook)

The company/brand must listen to the dialogue and participate with customers

Customer contribution is a large percent of the value/experience

Every customer has a personalized experience

Social graph connections drive discovery rather than search

The report looks at the value of Facebook — comparing the growth of the company to the growth of Google — as well as the rise of other key players such as Quora, The Huffington Post and Zynga, and how each of them effectively took over from a leader of what it calls the “First Internet.”

So by the brokerage firm’s reasoning, The Huffington Post took over from CNN (s twx), Quora took over from Yahoo Answers (s yhoo)– which in turn took over from Encyclopædia Britannica — Zynga has taken over from MiniClip, which took the place of former leader Electronic Arts (s erts), and Jive Software has taken over (or is taking over) from Google Docs (s goog), which took over from Microsoft Office (s msft). One of the few early Internet companies that seems to have what it takes to bridge this gap is LinkedIn, the firm says (although some might argue the opposite).

As part of the report, which also looks at the rise of players such as BranchOut — the Facebook-based business network trying to give LinkedIn a run for its money in that market — Wedbush also looks at Facebook’s potential market value, and comes to the conclusion that the company could be worth $234 billion by 2015. That’s up from a recent private-market valuation of about $75 billion and would put Facebook firmly in Google territory.

According to the analysis by Lou Kerner, who also does secondary-market valuations of private companies like Facebook and Twitter for the website Second Shares, the giant social network could actually have even higher profit margins than originally forecast (as high as 50 percent, he says), and could grab an even larger share of the growing market for online social advertising and marketing dollars (as high as 15 percent of the global market, the Wedbush analyst estimates).

There are some caveats worth keeping in mind when reading the report, of course. For one thing, some of the leaders it identifies could easily be replaced by something else. Quora, for example, may well have peaked in terms of awareness and growth after a recent surge in popularity, and it’s not clear whether it can continue and become mainstream in any real sense. And when it comes to Facebook and Zynga, the firm is part of a hot private market for the shares of those companies, and so has an obvious interest in making them appear as desirable and highly valued as possible (Kerner also owns shares in Facebook).

That said, however, reports like this one help put the spotlight where it should be: on companies that have been able to take advantage of the social nature of the web — what at one point was being called “Web 2.0” — and how that has allowed them to grow at a speed that hasn’t been seen since the early days of Google. Sometimes we are so close to these events and companies that it’s easy to lose sight of how big a transformation they have helped create in our online lives.

It also helps reinforce how difficult it is for even early Internet leaders to adapt to and take advantage of these changes, as Google is trying to do by bolting social features onto its services through moves like its recent +1 launch. Leading in one wave is no guarantee that one can lead in another — and in some cases may make that even less likely to happen.

Post and thumbnail photos courtesy of Flickr user Luc Legay