At first I assumed it was people typing the web address into their browsers, but the URL includes tracking codes, and I'd expect people to simply type in the domain.
Reason this is important is that I don't know whether to allocate these hits to my PPC campaigns on a pro-rata basis, or whether to assume they did *not* originate from PPC. Obviously this has a significant effect on measuring the conversion rates and profitability of campaigns.
So, does anyone have a source of statistics on the causes of missing referers? I've googled the subject without success.
TIA
Pete
Other potential causes include referrers being disabled by the user (personally I always disable referrers), sometimes when a link is opened in a new window, if the browser security settings are set to high, if the user is behind a corporate firewall, a proxy server or filter (eg. parental control), if the referring page is static and was called from the browser cache, if the page was bookmarked or if it is the user's home page.
Some more ideas in this old thread from 2002:
The further I drill down into this issue, the messier it gets. Seems to me there are so many causes of missing referers that the page hits have to be allocated on a statistical rather than factual basis.
Pete
The Referer header always has to be regarded as suspect since it is so easy to fake or break.
Rgds
Damon
