Linkedin makes money charging the need to contact someone that is not in your network (this is one of their main feature).
Until recently there were several options to overcome this:
a. to ask that person for a connection
b. to request an introduction
But nowadays, if you want to find someone that is not close to u (regarding the six degreee of separation theory), you can in less than 10 seconds. For sure, most of the people has a twitter, a site, a blog, a facebook page, not to mention that even if you google him for sure you’ll find a contact detail, either email either phone.
Is so much transparancy nowadays.