People who volunteer to evangelize for particular products are more likely to do so when the products are easy to talk about and from established marketers than when they're so unusual that they defy easy explanation. That's one of the key findings of a new report by word-of-mouth marketing firm BzzAgent.

Almost half - 45 percent - of the volunteers said they chose to promote products that were "easy to talk about," while 40 percent said they touted products from "a trusted name." Only 24 percent said their selected products were "innovative," 23 percent said they were "new and unique," and 21 percent said they were "smart."