I think this is a very good topic. I'd also like to hear from other ppl how they approach this.
It all depends on what you need tracked. For the most part,your web logs will track hits, http_refers, sort the keywords typed, if any. But you can augment this by doing your own logging of http_refers, or even campaign hits by supplying a refer id in your incoming links. Also, if yu have a registration area, think about doing a "Where did you hear about us?" tyep of survey. I leave the default choice to something that I know i do not advertise, perhaps the New York Times, this way, you can rule out any "lazy" users who do not read over this survey. As for tracking, once a user comes into your site, you log their visit, from where, etc. Do you want to track every step they make in your site? also, when a visit turns into a purchase, you want to stamp that as well, so you can better calculate which campaigns have a higher return of investment. With google adwords, you can track this, but I think it only tracks the sale if the user comes into the site and buys something all in the same visit. You might want to consider tracking the user with your own cookie, so you can better gauge buying trends. Like when a user comes in, looks around, 3 days later, comes in again, then a day later, finally commits to a purchase. Just some thoughts. Keep in mind also, you cant rely on http_refer
