Mario Sundar, the community evangelist for LinkedIn, has posted a chart of Nielsen’s March ratings which shows LinkedIn surpassing Facebook in growth. According to Nielsen, LinkedIn grew a whopping 319 percent since last year. This is in comparison to Facebook which grew almost 100 percent.

Percentages can be misleading though and these numbers also can be highly inaccurate as show with Google’s recent quarter and Comscore’s blunder. The report shows that Facebook only had approximately 25 million users in March, whereas Compete.com says Facebook had 31 million unique viewers the same month. No matter what numbers you look at though, LinkedIn is experiencing phenomenal growth.

This could be a direct result of the growth of social networking sites into demographics that traditionally stay away from social networking. As I wrote about this morning, the Boomer generation has an increasing number of people on social networks. Users over 45 now account for a whopping 31 percent of LinkedIn’s user base. Which demographic is experiencing the most growth though is currently an unknown.

Whatever the case, social networking is still booming and LinkedIn has proven its ability to experience continued growth even in the face of Facebook where business networking in now pervasive. Perhaps not all social networks need their own platform!