This from eMarketer is great.
Quick takeaways, and I use the net promoter basis [positive minus negative]. Word of mouth is the clear winner, but there remains some life in traditional methods.
The really bad category is to be avoided.
- word of mouth is most persuasive by far [57]
- newspaper ads beat TV [28]
- TV ads feature surprisingly strongly [25]
- collaborative filtering is lower than I’d expect (Amazon) [13]
- really bad advertising
- banner ads [-10]
- email spam [-38]
- telemarketing [-55]
- pop up ads [-60]
Source: eMarketer


If any of your readers are interested in more information on Net Promoter, as you reference above, they can visit the official Net Promoter website located at http://www.netpromoter.com. The site has resources including a discussion forum, blogs, and a job board.
Thanks Amy for your efforts, but not everyone is ‘there’ yet. Ron at marketingroi.wordpress.com makes some excellent points.