I don't understand LinkedIn (anymore). Their business model seems to be to source candidates to recruiters. This may be good for recruiters, but for candidates? I'm not so sure. It's certainly better to have an overall strong online presence (Twitter / Github (if relevant) / personal blog) than contacts on LinkedIn that don't mean anything. Groups are full of spam. The website is incredibly unresponsive. They bought…
> Our mission is simple: connect the world's professionals to make them more productive and successful. When you join LinkedIn, you get access to people, jobs, news, updates, and insights that help you be great at what you do.
LinkedIn targets all professionals, not just those that are tech savvy. Most people visit only a handful of websites in a given day; if Linkedin can become a 'good enough' destination for professional news, it has a good chance of becoming part of that handful of websites, if it isn't already. There's some good insight on that here: https://www.quora.com/LinkedIn-Acquisition-of-Pulse-March-20...
Linkedin as a company isn't just about one thing, like adding professional connections for example, much like Apple as a company isn't just about one thing, like making iPhones. As a company, their goal is to build product(s) that align with their mission, and if the stock market is to be trusted as a proxy of how well they're doing that, it appears they're doing pretty well: http://finance.yahoo.com/q/bc?s=LNKD+Basic+Chart&t=1y