I only reply when im pooking or its ones i like to keep in touch with. 9 times out of 10 youre just their product, ignore away, you wont burn any bridges. Yet you may not get the best job offers until you start acting which may not he what you want.
The best job offers come when someone knows who you are. To get there you need to have some sort of presence on the radar of the right recruiters. I have jumped in and out of recruiting and development so I'm not guessing on this. The product is the chemistry and courtship assistance, not the person. A good recruiter can help, a bad one can waste time. The same is true with a good vs. bad developer.