Successful professionals will keep that profile more up-to-date than on all the other standard branding material, ranging from website "abouts" to print backgrounders.
I found that out when I was researching a media pitch for a principal in a restructuring firm. I needed more data about her track record. Where I eventually found it was on her LinkedIn profile. Though brief, it detailed her accomplishments at the firm. Actually, it was so well done that, based on that model, I overhauled my own LinkedIn profile.
About a month ago I conducted a marketing campaign for my ghostwriting services to diverse kinds of technology organizations. Several times each day those receiving my email pulled my LinkedIn profile. Frequently, I write on animal companions and pet grief. Now and then veterinarians and animal advocacy groups review my LinkedIn profile.