Thing 13 Tagging

I really like the idea of tagging. I think people are used to bookstores and grocery stores that are nicely labeled. I think that subject headings get a little overwhelming for patrons in the library and that makes it difficult to look things up. As for putting this in practice, i do not know how it could be put into practice. I heard someone say once that theoretically it would be cool to get rid of Dewey since that seems to be confusing to patrons, but realistically how would books get reshelved with out a call number? Is there a way to integrate both? I am not a cataloger so that makes my head spin, but I do think eventually something will have to give.