A forum search on Webalizer will find a number of previous posts that have a) an explanation of the terms, plus a link to a documentation page on the Webalizer site that explains further (try a forum search here on "mrunix"), b) discussions about why there are discrepancies in the stats as reported by different stats programs. If you don't find that in these forums, a web search will surely turn up info. It gets asked a lot. There is also a page of info about it somewhere at the Google Webmaster Tools site.

There is no standard against which you can compare your results and declare them either good or bad.  Use the statistics from your initial months of operation as a baseline. If they improve in the coming months, that's good.