Is Linked In worth $1 billion? Who knows....

...at an investment level of $53m for c 5% of the company, the end valuation is monopoly money*.

GigaOm has as good a valuation as any for now:

So I decided to do a back-of-the-envelope comparison with XING with some of the publicly available data on XING, a European Social Network that is publicly traded in Frankfurt. It is a pretty good proxy for a business-focused social network, such as LinkedIn.

It has a market capitalization of about $300 million. It has has 5.71 million subscribers. XING had revenues of around $11.6 million at the end of first quarter 2008; about 70 cents per month per subscriber. That works out to about $52.30 per subscriber. For sake of comparison, Facebook’s reported $15 billion valuation works out to $125 per subscriber.

If you use those numbers, then LinkedIn’s rumored 20 million users are worth $1.04 billion.

The thing I like about Linked In is it addresses people who actually have money, and has a clear opportunity for a Freemium model. But when we see 20%+ investments in it we'll know what its really worth.

* Though I do wonder if many founders know what happens if it then takes a down round...its not the investors who get scraped. They must know that, surely.....