Type One: Information
readers bring to the text
This old information is what your particular readers can be counted
on to know. Here is a sentence from a document distributed to accounting
In the past, amortization of purchased software costs over
a five year period was required unless it could be established
that the software had a shorter useful life.
Although you may be unfamiliar with the term "amortization," tax
accountants know it well. In other words, for tax accountants "amortization" counts
as old information.
The author of this document wrote a very different version to give
to an audience of non-
In the past, you had to write
off funds spent on software at an amount prorated over a five
unless you could establish that your software had a shorter useful
For non-accountants, the term "amortization" may be
new and unfamiliar. Thus, the writer begins her sentence with "you" instead.
Human beings usually count as old information, and reader and writer – "you," "we," "customers," "our
firm," etc. – are always old.
Here's a somewhat more complex example. This is the first sentence
of an article in The New York Times (12/20/90):
The White House's
tortured handling of scholarships for minorities reflects both
the disarray in President's domestic policy management and a
for the civil rights agenda in the top levels of the Administration.
opening this sentence with "The White House's tortured handling
of scholarships for minorities," the writer assumes that we
know that there has been a tortured handling of scholarships for
minorities. That assumption is reflected in two ways: (1) the writer
uses the definite article "the," thereby implying that
we already share information about the tortured handling; and (2)
the writer also nominalizes "handle," as though it referred
back to a previous action.
Had the writer assumed no knowledge beyond the meaning of the words,
he might have written this:
 The White House [he assumes we at
least know that there's such a thing as the White House] tied itself
up in knots trying to retain scholarships for minorities this week.
 This tortured handling indicates that those who manage the
President's domestic policy are in disarray and that the top levels
of the Administration
are struggling fiercely for the civil rights agenda.
When the writer nominalized "handle" into "handling," he
changed a fully stated proposition (with a subject and a verb)
into a phrase. When writers collapse a proposition into a phrase,
signal that they assume the reader already knows that part of the
story: here, that there has been a handling of scholarships. It's
as if someone said, "George's cheating on the test means that
he won't graduate." That phrase, George's cheating on the
test, takes for granted that the audience already knows George
on the test. On the other hand, if someone said, "George cheated
on the test. That means he won't graduate," then that speaker
does not take for granted that the intended audience already knows
that George cheated.
By closing the first sentence in the article with "a fierce
struggle for the civil rights agenda in the top levels of the Administration," the
writer shows what in the sentence he expects to be new information
to his readers. The indefinite article "a" in that phrase
indicates that the writer assumes that would be new information.
But once introduced as new information, it becomes available as
old in the text. And that's the second kind of old information.
. . .
Type Two: Information readers learn as they read
The second kind of old information is information the text itself
provides. This information will be new when it is first mentioned
but becomes old thereafter. Here are the first three sentences
from the Tax Action Memo written to non-accountants:
 In the
you had to write off funds spent on software at an amount prorated
over a five year period, unless you could establish that your
software had a shorter useful life.  However, you can now
funds over a 36-month period instead.  To take the 36-month
option, you must have purchased your software after August 10,
introduced the idea of 36-month amortization (now old information)
in sentence 2, the writer can refer to this idea as simply "the
36-month option" in the beginning of sentence 3.
Type Three: Information the text implies
A third kind of old information is information that is not stated
in the text but that readers reasonably ought to infer, given what
we assume them to know. The New York Times article goes on:
That struggle resumed with new intensity from the moment Mr. Bush
up on the morning of December 12 to news reports of the Education
Department's decision to ban federally funded subsidized institutions
from designating scholarships for specific minority groups. 
Surprised and reportedly disturbed, the President ordered his chief
John H. Sununu, to find a way to retreat from the ruling, which
was not only politically damaging but also challenged Mr. Bush's
to minority scholarship programs.
When sentence 4 begins with "Surprised," the writer
assumes that anyone who wakes up one morning to disturbing news
surprised. The writer also assumes that we would expect as much:
he assumes that we will not be surprised that the President was
surprised. Incidentally, notice how the writer takes for granted
that we all
agree that Mr. Bush is committed to minority scholarship programs.
This kind of style in fact creates implicit agreement. In business
contexts, such a style helps to build solidarity with your readers.