Can't agree. While there are some evergreen postings, LinkedIn job applications still landed me a couple of interviews (and much more compared to cold applying on the company website). And then there's recruiters reaching out which landed me even more interviews + my current - genuinely great - job.
The recruiters reaching out to me are all for terrible companies or for non-remote roles in other areas of the country. It seems Glassdoor and others have better job boards than LinkedIn.
How else are you going to liquidity-stalk that company you left with some options or even shares?
I take my first cup of coffee with a little tea-leaf reading based on the activity of the CEO and my former coworkers. If you ever see more than 5 connections reacting/liking the same thing you know that HR or marketing sent out an email about it.
LinkedIn is a great place to talk to recruiters still. If you're not picky about where you work, you can find a job pretty fast by working with recruiters directly and skipping the cold apply.
