"Submitting a resumé to a website is about as useful as throwing a coin into a wishing well."
Not true if you are experienced, (and an engineer). The above is true only if your resume is not interesting. ie. 1. You don't have any position on interesting companies on your resume that are known for good technical talent. 2. You don't have any significant products, or side projects to show. 3. The company is not looking for somebody like you right now.
If you have shown to ship products (and good ones), then you always get a call back. Most startups do actually check and screen inbound resumes.