Yes, spamming is bad, and yes, recruiters should read your profile prior to messaging, but for practical reasons the actual outreach message is gonna be largely not personalized other than with your name. Reading an individual developer's Medium posts and then crafting an individualized message based on that is, like, the definition of unscaleable. It's like insisting that cars not be manufactured in factories anymore, but instead be lovingly hand-crafted for each individual owner, one car at a time. This is obviously economically impossible. Also, in practice, the actual response rate for way-personalized messages isn't much higher. It just doesn't make sense in practice.
If there are say 500 Node.js developers with the right amount of experience & CS degrees in a given metro area, the amount of time it would take to research each individual and craft a personalized message based on their Github or Medium posts or Stack Overflow answers or Twitter is literally 10,000x what it takes to just shoot each of then an InMail or e-mail. Again, a recruiter should read each profile to make sure they're on the right track, but the messages are likely going to be mass-produced
Without quantifying anything it's kind of meaningless. The point is that recruiting is a business process and that we should treat like any other type of process, by being systematic.
The information we need is how many interested people responded with a generic message vs. how many responded to the personalized message, and the amount of time spent on each approach. Note that 'responded' here is defined as 'I'd like to pursue this opportunity' or 'I'd like to learn more' which then leads to them pursing the opportunity. Not social niceties like 'I'm not looking but it's wonderful that you took the time to read my Medium posts, you're so different from the other recruiters', etc.
If there are say 500 Node.js developers with the right amount of experience & CS degrees in a given metro area, the amount of time it would take to research each individual and craft a personalized message based on their Github or Medium posts or Stack Overflow answers or Twitter is literally 10,000x what it takes to just shoot each of then an InMail or e-mail. Again, a recruiter should read each profile to make sure they're on the right track, but the messages are likely going to be mass-produced