difference between link objects and librarys

[David T Farning]

I am unclear as to the difference between LIBADD and LDADD.  Diffent 
resources seems to say different things.

Redhat's autobook states.
"A common difficulty people experience with Automake is knowing when to 
use a `LIBADD' primary versus a `LDADD' primary. A useful mnemonic is: 
*`LIBADD' is for ADDitional LIBrary objects. `LDADD' is for ADDitional 
linker (LD) objects."

*
From the libtools manual
"Libtool library support is implemented under the `LTLIBRARIES' 
primary.   Here are some samples from the Automake `Makefile.am' in the 
libtool distribution's `demo' subdirectory.  First, to link a program 
against a libtool library, just use the `program_LDADD' variable: "


From  
http://www.murrayc.com/learning/linux/building_libraries/building_libraries.shtml.
   Libtool libraries have the .la suffix, instead of .a
   We need to use _LIBADD instead of_ LDADD.
For instance
   lib_LTLIBRARIES = something.la
   something_la_SOURCES = main.cc
   something_la_LIBADD = sub/libsubstuff.la
But, what the difference between linker objects and libarary objects?   
The examples seem to be saying oppsite things!

Thanks
-dtf