Disadvantages of Page Tags

Dependence on JavaScript and Cookies: Page tags are
reliant on JavaScript and cookies. JavaScript unmasks key,
distinguishing information about the visitor (the pages they are looking
at, the browser they use, etc.), while cookies are responsible for
storing all of this information and determining visitor uniqueness. When
users turn off JavaScript or cookies, it reduces the quality of the
information.

Dependence on Cookies as a Unique Identifier: While
client-side solutions profess to provide human visitor information, they
actually provide information about web browsers. The following
assumptions made in client-side data collection raise the probability of
error:

• A single user equals a single browser
• A web browser will not have multiple users
• Cookies are not likely to be turned off
• People allow their browser’s cookie cache to accumulate
• People are loyal to a single browser
• People are reluctant to spend money on a new computer

Adding Page Tags to Every Page: Without a built-in
header/footer structure for your website, this step will be very time
intensive. Those who already have this structure set up can simply
insert the page tag in a common header and footer file. For static sites
(that don’t use server-side includes), this tag will have to be
manually inserted on every page to be tracked.

Tag Implementation Complexity: The complexity of
your page tags and vendor selection will determine how long the project
takes. Tagging can be done in a matter of hours or it can take weeks or
months.

Page Performance: Visitors may experience a change
in the download time of your site, as the JavaScript code needed to
track your pages is never zero-weight. Vendors that tout otherwise are
incorrect.

Time Limits on Data Storage: Many page tag vendors cannot store collected data indefinitely due to disk space and rising storage costs.

Limits on Type of Data Collected: Page tags have
some restrictions in their ability to report on non-HTML views such as
Adobe PDF files, error pages, redirects, zipped files and multimedia
files.

Privacy Concerns: Privacy is a hot topic for
consumers and legislators. Issues abound concerning the types of data
collected, how they are used and where they are stored. Because of this,
most client-side web analytics vendors issue a privacy policy notifying
users of data collection procedures. It is a good idea for their
clients to post a privacy policy covering the client-side data
collection as well.

A final drawback of the client-side applications is their inability
to capture data from users who do not have JavaScript enabled (i.e.
cookies).