I'm trying to figure this out as I'm dumping outside counters and have my own script counting hits.
At first I only counted someone as a "unique" if they hadn't been to the site in 24 hours...but I realized the fallacy of that since if a surfer visited the site a few times a day at different times they would NEVER count as a unique again.
So now I have tried every 12 hours...but that is giving me figures that are closer to third party counters "First Time" numbers.
I have heard time intervals as varied as 24 hours all the way down to 30 minutes.
Does anybody have any experience in this that could give me some idea of an industry "standard" (even though I know one does not exist) time interval to count a surfer as a unique?
Doing this project has given me some interesting insight into ACTUAL numbers of people visiting a site and sure does explain to me how some sites jumped so fast in "uniques" a few years back!
LOL! I guess a little tweaking of the time interval and you could be showing a few million uniques and raising your ad rate...but I'm sure nobody would do that!
Anyway, any ideas?