Real-world and virtual networking both have their own particular strengths which can complement each other pretty neatly to help you find a job. You can read more about the respective advantages of online and face-to-face networking here.
With so many recruitment agencies and industry colleagues active on online social media, it’s one giganitc grapevine through which companies can find people like you, and where you can find out about jobs (some of which may not be advertised elsewhere). However, it lacks the important cues us humans use – body language, personal chemistry, etc. – to make deeper connections with each other.
In short, use the Internet to grow a large network by connecting with colleagues (and colleagues of colleagues) in organisations that you like, or who share goals similar to yours; sow the seeds of collaboration with a select few by getting involved with them in online interest groups and discussions; and then ideally cement these relationships in person (or failing that, by phone or video call).