I'm interested in a couple domains that appear to be unused, but I'm having trouble contacting the owner. How do you go about making the offer? I've emailed a couple contacts now obtained off of whois and it seems they never reply.
First of all, don't assume the domains are unused. You have no way of knowing this. I have domains that are critical to my infrastructure but don't necessarily have a web site (or even public DNS records). I'll never sell them. I have others that are look-alike domains that aren't activated in order to prevent conflict with my other domains. I'm unlikely to sell these, either.
Secondly, and this is really important, make your offer as professional and informative as possible. I never reply to offers from freemail addresses that amount to something like, "Hey, I'm interested in buying a domain that you don't appear to be using for an awesome project I'm working on. Please reply ASAP. George". You don't have to divulge your business model, but at least include the name of the domain you're interested in, your FULL name, a phone number, and preferably a company name and/or related URL. Consider including your offer in the email, since it's more likely to get a response if it's at all worth considering. Serious offers are much more likely to get a reply, even if it's to say, "Sorry, not interested."
If you call and leave a message, include the same information. But keep in mind that I probably won't return a long distance call, so consider saying that you'll call back at a certain time, and do it. This will help to show that you're seriously interested.
Whatever you do, don't file a complaint with the registrar or try to initiate an unauthorized transfer. This will only annoy the domain owner and could destroy your credibility.
Finally, understand that the domain owner has no obligation to respond to your offer in any way. If you really want a response, follow up a couple of weeks later, and be prepared to make a serious offer. If you don't want to be considered a pest, stop after 3 attempts and give it a reasonable long rest before trying again (6 months to a year).
How does this work? I'm not following you. It would seem that the less people/systems that know about a name, the less critical it is.
I've used domain names with no public DNS for corporate Active Directory domains. They might have a different domain for their website, but by registering it you are covered.
Always specify the domian name and make your outreach email as professional and formal as possible. I never include an actual offer so I can at least get them to reply (if you offer too little, they may not even reply). I never discuss the reason for purchase. The first email is only to determine their interest and start the dialogue.
If they fail to respond in a week (it takes time), I call the phone number listed on the whois record and try the personal touch.