I'm just curious what the general consensus is. For as long as I can remember, UV meant unique visitors and 'uniques' meant the same thing.
There are a lot of different statistics packages available which use different parameters in determining exactly what a unique visitor is, but in general, it was historically unique IP addresses on a daily basis.
With Google Analytics becoming widespread, the meaning has changed and 'visits' is different from 'unique visitors' which is in turn different to 'unique pageviews'.
I find some numbers which webmasters report (across the web on different forums) to be unbelievable if I use my own definition.
What do most people use to determine "uniques" or "UVs"?
Something tells me your visitors don't include an office that has an unknown number of people sharing half a dozen IPs, including multiple humans using the same computer, with little-to-no control over what The Technicians may choose to come in and do over the weekend.*
Or, conversely, mobile devices whose IP changes from one file to the next.
For after-the-fact tracking I've changed over to matching only the first three pieces of the IP, in conjunction with matching UA. Fortunately I don't get an enormous lot of people switching browsers midway-- and the ones that do, tend to be involved with some specific page that will be flagged for other reasons.
That's all assuming that you really need to count unique visitors. If you've got a reference-type site where the only user action is to look something up and be on their way, does it matter whether it's the same user or a different one? It may be more useful to count number of lookups.
* Latest at the library: A routine upgrade, wrapped up by-- as usual-- neglecting to reset the defaults. Result: the series of actions that used to lead to a routine end-of-day shutdown now locks the computer so you have to go find someone with the right password. I also liked the part where the only thing you can do without a password is log on to Admin, revealing all kinds of things that are supposed to be disabled on a public terminal.