How does something like Statistically Improbable Phrases work?
According to amazon:
Amazon.com's Statistically Improbable
Phrases, or "SIPs", are the most
distinctive phrases in the text of
books in the Search Inside!™ program.
To identify SIPs, our computers scan
the text of all books in the Search
Inside! program. If they find a phrase
that occurs a large number of times in
a particular book relative to all
Search Inside! books, that phrase is a
SIP in that book.
SIPs are not necessarily improbable
within a particular book, but they are
improbable relative to all books in
Search Inside!. For example, most SIPs
for a book on taxes are tax related.
But because we display SIPs in order
of their improbability score, the
first SIPs will be on tax topics that
this book mentions more often than
other tax books. For works of fiction,
SIPs tend to be distinctive word
combinations that often hint at
important plot elements.
For instance, for Joel's first book, the SIPs are: leaky abstractions, antialiased text, own dog food, bug count, daily builds, bug database, software schedules
One interesting complication is that these are phrases of either 2 or 3 words. This makes things a little more interesting because these phrases can overlap with or contain each other.
