I don't think they're dead - but changing communication trends have created new challenges. Calling someone on their cell phone is considered rude and people are increasingly ignoring their office phones. As for email, we are inundated with an ever increasing load in email - making cold emailing ...
Not sure there is a definitive, one-size-fits-all answer, but I can give you my experience. I've had much better success with multiple touch points than the single blast. I would specifically target folks who opened, but didn't click the first email, and send them a second email with a modified...
CJ.com or Linkshare.com. If not there check Viglink.com