Within Google Analytics is a tool called goals, which presents itself as an e-commerce tool. If you are running a web comic site, it would appear to have little use, unless you are also selling merchandise. However, I have found a nifty way to adapt it for comics.
Setting a goal for an e-commerce site is straightforward. Say your site has three pages of merchandise, a shopping cart, and a checkout. An obvious goal would be to have a customer visit each of those pages in that order, ending with a purchase. You would set up a goal that listed the catalog pages one by one, then the cart, then the checkout. Each day, Analytics would report how many site visitors completed that path. You might change your merchandise mix or presentation order based on what you learn.
Now imagine a comic site with one story in progress and three stories in the archives. Right now, it is difficult to tell what visitor behavior is regarding the archived stories. But by establishing one or more of them as an Analytics goal, you can find out. You simply enter the goal as page one of a particular story, followed by page two, and on through to the last page. Each reader who visits those pages in order will be a goal completion. Gag panels and short strips can select a run of ten sequential pages from the archives to see how many people are sifting through.
If your archives are not getting traffic, you may need more guidance links and information for visitors. People want to know how long a story is before they plunge in, for example. You may find you need links to archived stories featured more prominently on your main page.
Google Analytics updates daily, and a section called Goal Conversions will tell you how many visitors completed your goal each day. Note how I placed links on my comic's homepage to encourage archival navigation, boosting my goal conversions.
Your archives are key to building a long term relationship with readers. They help readers know your characters better, and forge a relationship that is deeper than readers who have only followed updates from a certain point. Measuring viewer traffic in the archives is the first step toward immersing readers in your comic and turning them into loyal fans and afficianadoes.
I've noticed that some archives feature early, tentative work, followed by stronger material. There comes a day when this stuff should be pruned, perhaps placed in a sub-archive for the curious. Link to your strongest archival material if you want to make goal conversions.
Above: An innocent girl is corrupted by web comics. Photo copyright Stephen Ausmus.