Our company is looking for site log/stats that include number of users to the site and page, and user duration on the page. (We are writing the sitelog to the SQL database. Looking at the SiteLog table, I only see the IP address being captured for both UserHostAddress and UserHostName, which will I don't think gives us each unique user that may be coming from a single IP address.

Am I missing something in my understanding, or is it not possible to break the stats down by unique users as opposed to IP addresses.
If that's true, are there any 3rd party modules or separate apps that would be able to do this ?

 

Regarding unique users, the only way to tell for sure with SiteLog is if the users log in (so you'll then have the users' unique USERID values).
 
Regarding time on page, the only way to get decent info from SiteLog is to have a very large data sample.  You are, at best, only guessing at "time on page" based on the timing of successive page requests from an IP.  As already mentioned, you are not able to distinguish unique users from the same IP based only on the SiteLog plus, as Sebastian mentioned, use of the BACK button can foul your attempts to trace a user's path / timing.

Google Analytics would be a good addition if you're not already using it.  GA gives you a wide range of stats to compare your own stats against (including its own guess at "time on page").  I like to use GA in conjunction with a DNN-based stat package and my own home-grown stats as derived from various DNN tables.  Between the three I feel I get a decent picture of what's going on with a site.
 
-mamlin