Difference between delimiters versus tagging?

[Roger L Costello]

Hi Folks,

Is there a difference between 

    isolating something with delimiters so that the start/end of the data can 
be found

and 

   tagging

?

I don't see any difference. Consider this XML snippet:

   <altitude>1000</altitude>

That is an example of tagging the data (1000). Isn't the start tag an initiator 
and the end tag a terminator? The tags isolate 1000 so that the start/end of 
the data can be found. Yes?

/Roger