Linkedin has grown and grown in the years since 2006 when I first started using the internet in a serious way for business. What is great about this site is that you can follow easily anyone who follows you, and once you have a network you can follow the people who are members of your followers network, sorry if that sounds a bit convaluted, but it means that once you have a network you can easily expand it.
I've been using Linkedin for years you can find my personal profile on Linkedin easily.
There are many cool features about this site now, you can post articles and I have a few live such as this one Company Information for free, it needs a bit of work to expand it further, but it is a way of publishing content in a very well respected and high profile place.
If you have a company then you can easily create a profile about that for example my Business my liinkedin
Profile for Compelling Media.
All of these are a great way to market yourself, push your ideas out to your network of followers and get a bit of attention to your business.