Can you over advertise?

[linkus86]

I just wondered if over-advertising was a possibility. It just seems to me that the past 5 years a handful of companies have done just that. A past example is GEICO. For a while there I felt inundated multiple times a day, every day by Geico commercials both on TV and online, now a days it is E-surance. I understand the whole basis of advertising and marketing is to get your product and the ideas behind it into the consumers minds, but is there some sort of equation that is being sought that shows too much has a negative effect?