what's there with the tag??

tagging.
what do you mean by tagging?
'tag'..

there are many tags in life,
'price tag'
'tag line'
'name tag'

and whatever tags there are..
i'm very curious though, as to what 'tag' usually means to someone..

i tag you in a post,
you tag me for the location...

are you tagging for informing?
are you tagging  for sharing?
are you tagging for telling?? ( here merely means that the one tagged is already "tagged")

p/s: you can't tag people without any purpose,, right?