• Local IP Exclusion: Have you blocked local IP addresses as well as your vendors' so that their activity doesn't get included within your results? If your site receives tens of millions of page views monthly this won't have a huge impact, however for websites that receive only 1,000-10,000 page views, this will skew the data.
• Sub Domains: Not all analytics solutions automatically track activity on a sub domain of a website, so make sure you either have activated the sub domain in the code or in the analytics admin area. Here's how you do it in Google Analytics:

  _uacct = "ACCOUNT NUMBER HERE"; _udn = "DOMAIN HERE"; urchinTracker();

• Email/Download Links: Contact forms and newsletter email registrations aren't the only way to measure the number of leads and conversions. Don't forget to apply appropriate tracking for links to emails and downloadable collateral. Here's an example of how to track a link in Omniture's SiteCatalyst:

  a onclick="s_linkType='o'; s_linkTrackVars='s_events'; s_linkTrackEvents='event#'; s_linkName='Contact us email@domain.com'; s_events='event#'; s_lnk=s_co(this); s_gs(reportsuite);" href="mailto:email@domain.com">email@domain.com /a

• Development vs. Production: During the publish from the development to the production environment make sure you're referencing the correct attributes and files on the production server.
• Paid Search: Analytics providers often don't automatically attribute Paid keyword referrals to PPC unless there is an admin setting turned on or the referring URLs have appropriate parameters appended to them. Forgetting to setup Paid Search tracking can result in the inflation of natural/organic search referrals.
• Tagging Error Pages: Error pages are part of your site as well and a great way to determine if there are any navigational issues throughout the website, so make sure they're tagged.
• Internal search: Want to know what users are looking for on your website? Without being able to identify the internal search queries, this task becomes increasingly difficult. EpikOne has a useful post on how to track internal search queries using Google Analytics.
• QA and Testing: This should be an obvious one not to forget but after a long implementation, QA and Testing often don't get integrated into the implementation plan.

There you have it, 8 items to permanently add to your checklist for a proper web analytics implementation.

Download the Checklist - PDF!