LinkedIn looks like it's in an all-out race with Facebook to be the first social network to go public.The site focused on business relationships has raised a $53 million round at a valuation of just over $1 billion, according to various online reports.The latest fundraising, most from existing investors who've already put in $27 million, looks like a major step on LinkedIn's way to an IPO. While it still might solicit or attract smaller investments in the future, at that valuation it's going to be hard to raise another large round of private equity to fund its growth.  Founder Reid Hoffman said as much to VentureBeat when he spoke of the company's discussions regarding going public.The only thing that might ... [ Read more ]