Which are the most important concepts of traffic analysis, and what
are the best ways and tools to measure site traffic and analyse web
server logs? What are the "official" definitions for visitors, hits,
page views, unique visitors and other important concepts for traffic
analysis? Where can I find articles about this subject?

Hi Kischi !

Website statistics are not always easy to dig through, especially raw
data logs, so many webhosts provide one or more software packages to
analyze the stats.

Even then, many people don't understand the value of the information
they're looking at, nor what helps and what doesn't. Software like
Webalizer and/or Analog offers a way to look at the statistics, but
what really is important?

Starting with your question about the definitions:

* Visitors
==========

Whenever a request is made to the server from a given IP address
(site), the amount of time since a previous request by the address is
calculated (if any).

These figures can sometimes be skewed. For instance, if the a site's
stats are timed to time out after a set amount of time, but the
visitor returns or takes longer on the site, it can be shown as two
visits. The same applies if a visitor is on a site before and after
midnight, it can be counted as one visit on the first 'day', and one
on the second. So, there is bound to be some small deviance from the
number of unique visits or unique visitors shown.

* Hits
======

A hit is basically any file served by a server. So if you view a web
page with five graphic files, the number of "hits" (or files served)
would be six for that page. One for the page itself plus five for the
five graphics, equal six 'hits'.

* Page Views
============

A page view is, well, a page view. How many times has that particular
been viewed? If one visitor returns to that page 10 times, that's one
visitor and 10 page views.

* Unique Visitors
=================

See the definition above. The problem, again, can be at what point,
what criteria, is used to determine that even a returning Visitor
becomes a unique Visitor.


"Official" Definitions
======================

There are no real "official" definitions, but they are generally
defined along the loose definitions I mentioned above.

Howver, Netlingo has a set of definitions for you here:

* Unique Visitors -
  - http://www.marketingterms.com/dictionary/unique_visitors/

* Page Views -
  - http://www.marketingterms.com/dictionary/page_view/

* Hits -
  - http://www.marketingterms.com/dictionary/hit/

There is an alphabetical bar across the top of each of Net Lingo's
definitions pages which lets you look up the words you may be looking
for.


Webalizer's Definitions
=======================

If your host offers Web statistics usingi Webalizer, their definitions
have been reproduced on this SA Texas Communication Network site:
  - http://www.satexas.com/support/domainhosting/webalizer_defs.phtml


Analog's Definitions
====================

If your host offers Analog as a statistics analyzer, their definitions
can be found here:
  - http://www.analog.cx/docs/reports.html


Which statistics are important?
==============================

What's important? It depends on where you are coming from with
relation to your statistics. Small business owners usually want to
know what page their visitors land on, which pages they visit, which
page the leave the site from.

Running a 'special offer' or want to know how a particular ad campaign
is going? Then you'd be interested in the visitors to that page, and
where they are coming from (in other words, which referral measures
work best).

I have managed to locate a book and a few articles on Web Stats, but
most of the information is obviously tied into Website marketing.

The book is "Web Site Stats: Tracking Hits and Analyzing Web Traffic"
by Rick Stout which is available on Amazon.

Some of the articles I found:

* "Who's Counting? Ratings Data is Beginning to Stream In",
  by Lawrence Pintak 01/04/01
  - http://channelseven.com/newsbeat/2001features/news20010104.shtml

* "Analyzing Consumer Activity Leads to Sales",
  By Carol King, January 22, 2001
  - http://www.internetnews.com/ec-news/article.php/4_566841
 
* "Evaluating Website Statistics", Performance Marketing Group
  - http://www.pmarketing.com/images/sitebacker.pdf

* "Mining For Gold ...In Your Web Traffic Logs", CyberSpeaker
  - http://www.cyberspeaker.com/mininglogs.html 

* "Beyond Hits", CyberSpeaker
  - http://www.cyberspeaker.com/beyondhits.html


Search Strategies Used
======================

 - definitions: website statistics
 - articles: website statistics


Hope this helps figure out what all those stats mean.

Best regards,
Serenata

This answer was useful! Thanks! :)