Don’t you just love what the penetration of broadband and the web has done to us? When Jeffrey and Bryan started Future Now in the late 90′s, one very real challenge they faced was the "my [insert distant relative here] is in computers" syndrome (note: the third-cousin-twice-removed wasn’t in marketing though
Now that Bryan chairs the Web Analytics Association, and is one of the longest running authors on ClickZ, not to mention a NYTimes, WSJ and USA Today best selling author (twice) we no longer typically run into this type of misperception. That being said, there’s still the occasional "I know a few things about Search Engine technology, therefore I’m an expert in Marketing" (Descartes would be so proud), and when they pop up, it’s pure comedy. That is, until you stop to consider that some people out there might take this "advice" seriously, and then it’s purely frightening.
A quick tip, if you want to learn Persona creation yourself, there’s more than a few excellent resources out there (and none of these experts will show you a complete persona in merely a few paragraphs, but if they do, don’t walk, run for the hills).