Every day I seem to get an email saying I am perfect for a Java or Oracle or other tech job because someone did a key word search on a job board and just messaged everyone. Sure they might toss in a statement to refer someone else if this is "not quite a fit" for me. What does this say to candidates that see your message? How validated do you feel? It makes me feel like the person sending the message has no concern what my background is and is just tossing things against the wall hoping something sticks.
Are you a culprit of this technique? If so, I want you to consider one thing... when you reach out to someone, you have one chance to make a good impression and empower someone to assist you in some way. By approaching someone with a developer job when they are a recruiter or sales person (or anything that is not the right role), you are saying to them "I don't really care about you unless you are an actual fit for my job" and it terminates most desire by others to assist or even consider your need. Is it a good use of your time or resources? Is it worth the potential negative image you cast of yourself on people who could be future sources of candidates or jobs?
There are automated systems out there that manage this "Spamming" and people are not actually physically sending messages. This does not make it any more justified. It actually makes the process worse. What happened to the resume review process? Has it gone the way of the phone sourcing techniques that have been lost over the last 10 years? I only want one thing for you to take from this. Your image is the one thing that you will always have. How do people see you?