Tagging

No, not that tagging, the kind of tagging you do on websites. Tagging is, simply put, indexing a blog post by identifying and listing keywords. NewMexiKen experimented with it last week but found it to be pretty much a pain with so many topics (for example, the birthday posts I do). So I stopped.

But it occurs to me, why tag anyway? If you have full text search, as this site does and as the internet does, why do we need to tag?

What am I missing here?