Where are they coming from?

For most sites, the largest single source of traffic will be AOL. For the Web Developer's Journal (which is aimed at intermediate-to-expert computer users), it's about 4%. Since AOL has a consumer slant, one usually assumes that visitors coming from AOL are more likely to be computer beginners than experts. The more your site appeals to the less computer-savvy, the higher a percentage of AOL hits you should see. If the thought of all those beginning Web surfers makes you see dollar signs, but your AOL traffic is in the single digits, then here's an area to work on. Make sure you're listed in AOL's directory, AOL Netfind, and consider adding content that will make AOLers feel welcome (a big flashing logo that says "Welcome AOL users?" - I don't know).

Behind AOL you'll see some of the other mega-ISPs, such as Uunet, Mindspring and Netcom. Here's a tip for you: Our traffic from Time Warner's Road Runner service has gone from zero to about 1.2% in a year or so. I don't know what that means for building traffic, but it sounds like a stock to buy!

Top Users

If your site traffic is high, then any entity that makes it onto the list of top users is unlikely to be a human. Most of these will be either a spider or a cache. A spider is an automated program that visits your site for the purpose of indexing it for a search engine. Obviously, spiders are welcome, but they won't be buying anything (a bit like journalists, actually), so it's interesting to get a rough idea of what percentage of your traffic is being "lost" to spiders.

Some large ISPs "cache" frequently-requested pages (that is, store them on their local machines instead of retrieving them from the Web each time they're requested), in order to save bandwidth. Caching is an important issue if you run an advertising-supported site, because page impressions delivered from a server cache will not be counted by your ad rotation software, and thus you can't bill for them (Actually, some of the higher-end packages try to compensate for this in various ways. See my comparative review of ad-management packages. It's important to compare the traffic stats that your ad-rotation package generates to the stats from the server log files. The former should be lower by approximately the amount of impressions being cached. If the discrepancy is substantially larger than this, there may be some technical problem that you'll want to find and fix.

Visitor Browsers and Operating Systems

The more advanced analysis programs can give you a breakdown of your visitors by browser version and/or OS. Some Web servers keep this information in a separate log file, called a "referrer log" (traditionally misspelled "referer").

Looking at your visitors' browser and OS versions can give you a rough idea of how computer-savvy they are. Advanced users tend to have the latest browsers, and are more likely to use NT or Unix. If a large percentage of your visitors are using old browsers, and a large percentage are coming from AOL (see above), then you may assume that many of your visitors are newbies. Of course, this is not absolutely true, as many employees of large companies have no choice but to use whatever browser and OS version their IT department has decided to "standardize on."

As a rough guideline, however, this has two implications. First, if a large percentage of your visitors are using older browsers, then take it easy with advanced design techniques like Style Sheets, Java and Javascript. Versions previous to 4.0 often choke on the latest doodads, even if you have a script to detect the browser type. Second, if you can get an idea of how tech-savvy your audience is, you'll know what kind of content to concentrate on.

Insights from your Error Logs
There's gold in them there log files!
Who's sending them?