It is a tradeoff. If you are looking for a job, or are new to the industry, linkedin is better than trying to build a professional network otherwise. After you

It is a tradeoff. If you are looking for a job, or are new to the industry, linkedin is better than trying to build a professional network otherwise. After you have been in the industry for, say 15 years, and pretty much know most of the people working in your space, are highly specialized, then the recruiter emails will feel like spam. My guess is that for the first case, you aren't specific enough about yourself, so recruiters have a good chance of reaching you, based on your profile. After a certain amount of time, your profile readily doesn't distinguish your interests clearly. For example, a java developer tag at the start of one's career is quite different from a senior java developer who has understanding of internals of JVM. Recruiter may not know about the second case enough to be of much help.