Yesterday I posted on how people didn't really want to watch ads in exchange for free online video. Similar stories have been written about mobile devices and the slowness with which people have become comfortable with ads being delivered to them.

Next up are GPS devices. While the gadgets are beginning to become more popular, with 30 percent of U.S. households now having one or planning to buy one this year, their usefulness as an ad platform remains murky at best. 75 percent of respondents have voiced extreme displeasure at the thought of receiving unsolicited ads on their devices. That's likely because GPS systems are utilitarian in nature, serving to replace paper maps and make finding things easier because of the ability to search.

Less than half of respondents to the survey, 44 percent, even express a willingness to have directions to restaurants and attractions delivered without their asking for it. While the MediaPost story doesn't give explicit numbers on this, it's easy to assume based on the other responses that a good deal of GPS users would be open to ads being served to them if they were permission-based or were part of a profile the user had filled out signaling certain areas of interest.