To some extent, if you don't have a LinkedIn you don't really exist within the job market - which is fine I guess if you never intend to change jobs but might be something you do want to do some day :)
I'm actually curious why you wouldn't have a LinkedIn?
Besides finding engineers, what does LinkedIn provide you as a hiring manager that a resume would not? (Assuming an online resume or a pdf has links to company information, references, etc.) I can't imagine anyone actually puts stock in LinkedIn "endorsements" or "recommendations".
We don't message it, but the last two fields are optional. Truth is we won't be able to handle every candidate that comes through yet so we're working in batches. The more information we have on people, the more we can prioritize them.
That being said, I'd love to chat -> [email protected]. I'll make sure you don't fall through the cracks.