A recent study suggests that weak ties on Linkedin are better in helping people find jobs:

If you have a LinkedIn account, your connections probably consist of a core group of people you know well, and a larger set of people you know less well. The latter are what experts call “weak ties.” Now a unique, large-scale experiment co-directed by an MIT scholar shows that on LinkedIn, those weak ties are more likely to land you new employment, compared to your ties with people you know better…
The notion that there is something especially useful about the more tenuous connections in your social network dates to a highly influential 1973 paper by Stanford sociologist Mark Granovetter, “The Strength of Weak Ties,” from The American Journal of Sociology. In it, Granovetter identified weak ties as a key source of “diffusion of influence and information, mobility opportunity, and community organization.”…
All told, the experiment involved around 20 million LinkedIn users, who over the five years ended up creating about 2 billion new connections on the site, recorded over 70 million job applications, and wound up accepting 600,000 new jobs identified through the site…
“Moderately weak ties are the best,” Aral says. “Not the weakest, but slightly stronger than the weakest.” The inflection point is around 10 mutual connections between people; if you share more than that with someone on LinkedIn, the usefulness of your connection to the other person, in job-hunting terms, diminishes.
The general idea is the people more removed to you but still in your network can access opportunities that close connections do not have access to. Reach out to the edges of your network and there are more options.
Now it would be interesting to see how LinkedIn and other similar platforms take advantage of this knowledge. Many social media platforms want to connect people. But, what if having more ties and increased interaction with other users is actually a negative feature for jobs?
Or, I imagine there are strategies for social media users to create an excellent set of weak ties rather than connect with people they know better. Why connect with people close to you when you could amass weak ties that could come through big later?