LinkedIn CEO, Jeff Weiner, proudly announced this week that his professional network was now responsible for connecting 100 million people. His blog post states that the social network is now growing at the equivalent of one million new users every week.

Impressive numbers no doubt and an even more impressive milestone, but it is no less than LinkedIn deserves. Such has been its success since its inception in 2003 that as a professional today, you’re either LinkedIn or LeftOut!

In his excellent blog post on the topic, Paul Gillin (@pgillin) points out that unlike trendier social network counterparts, LinkedIn is unlikely to be a success story that has Hollywood knocking on its door. What’s more, it has none of the ‘cooler’ functionalities like chat and photo sharing that has been the key to the success of other social networking giants (both past and present).

What it does have however is an array of applications designed to make b2b communications and networking a simpler and more pleasurable task. It has built its popularity on its ability to connect people, help them grow and develop their careers and businesses, and allow professional people to ask and answer the professional questions that are important to them.

The recent introduction of company-focused tools such as product and companies has only strengthened its worth to b2b organisations – just ask any Aspectus client how it’s adding value to their business!

So for all these reasons we tip our hat to LinkedIn – here’s to the next 100 million.

And in more social networking milestone-making news, Twitter is five years’ old this week. In just five years, the 140-character, micro-blogging site has revolutionised electronic communications, social lives, and news reporting across the world. Many happy returns!