Herman Cain may have very limited political experience and lack policy depth, but so far he’s  proven to be a master at branding himself.  When asked to use one word to describe the candidate, voters’ top answer for Herman Cain is 9-9-9. This is an impressive messaging accomplishment. From Pew research:

Just compare the top three words people use to describe Cain with the words chosen to describe Romney and Perry.

The top thing people associate Cain with isn’t something in his past or a personal/physical attribute or a perceived flaw. People primarily associate Cain with his 9-9-9 tax plan for the country. When people think of Cain they inherently think of his platform; that is a something almost any candidate anywhere would envy.

This is also why the other Republican candidates have been really focused on attacking the 9-9-9 plan recently.  Since voters closely associate the plan with who Cain is, if his opponents can make the 9-9-9 plan unpopular, that should do real damage to his candidacy.