Be wary of assuming that answer machines will be used. I'm 26 and I've never used an answer machine. Maybe accidentally. I'm probably not going to leave you a message because really few people listens to the message. I'm certainly not going to listen to a message someone leaves me. This is what SMS is for, I think.

I don't comprehend the thinking behind not listening to voicemails. Why have a voicemail box, then? You're just making anybody who does leave a voicemail think you're ignoring them on purpose. Is it people who didn't purposefully purchase and setup the voicemail feature, but it was automatically enabled?

Some operators have it as default - that's how I got one before. I think operators have stopped doing this now, at least where I live, so it's not a problem anymore.

So, it isn't actually success that kills the network, it's just the spammers. What else is new.

One could argue that it's success (i.e. it's popularity and commoditization) is what created the spammers.

I once got a call from a masked number where the guy was trying to scam me by telling me his "friend" was going to kill my brother unless I sent him some money. I didn't fall for it (the only credible info he had was stuff I told him), but it made me wary of unlisted numbers.

Personally I think masked numbers should be phased out entirely.

I had a series of spam calls a year or two ago where the caller's number was the same area code and first three digits as mine. At one point I even got a call from an irate Mexican woman who claimed I'd just made one of these calls to her. I guess the telemarketers figured out people are more likely to answer calls that look like they'really local, even if they don't recognize the number, and they had some way of spoofing it.