I think it is a nice idea, but if you give a plain textareatext area for each tag, it will be not that easy to use and kind of confusing. However,I still like it.
Moreover, it will better if at lest onleast one of textareathe text areas is required and not all of them are optional. Beside, some of the tags will not have any textareatext area such as Ubuntu 10.10 or 32-bit.