I received a call as well, and didn't receive a voice mail either. On my iPhone it says from South San Francisco Bay Area. I live in TX and don't know anyone from there so I don't know why I would have received a call from there.
This number showed up as "IVR" on my caller ID. The call came at 4:04pm today (I was outside). No message. I've received almost a dozen variety of calls over the last couple of days, I'm sure it's because of a new website where I posted my resume (but don't remember which site, maybe Monster). One caller wanted to set up a meeting with me - Amway-type pyramid business. I don't want to go to school, I went to classes JAN-DEC 2011. The most recent call (3 different ones today), I answered on the 3rd ring, said "Hello" a three times (growing more aggressive), then talked to dead air - waiting for ANYBODY to pick up so I could give them a piece of my mind - only to end up getting disconnected. I'm sure it's computer-dialing, and one of the pigs in the sty was not available to switch to the computer's message of "HEY! A live one answered".
Great! I just Googled "IVR"; at least that's honesty in the name.
Obviously, the National Do Not Call Registry does not apply to robo-calls.
I signed up with the DNC registry and my telemarketer calls tripled over a 2 week period. DO NOT bother registering with them unless you want more telemarketing calls. Someone there sells the information. There is no way I would have received so many new telemarketing calls because I rarely sign up for anything online. I tried to get my numbers off of the DNC and was told it would take 30 days. I ended up changing my phone number, which is a major hassle, after 60 days of daily telemarketer calls. I didn't receive nearly as many until I registered with the DNC. :(
The DoNotCall Registry kicks in ~30 days after you list your number but during those ~30 days, you can still be telemarketed to. If a telemarkerter manages to figure out your DNC status, you may be blitzed with calls but legal telemarketing calls should stop after the ~30 days. All calls after that are abusive telemarketing or scammer calls.