Everyone wants to know who is reading their site. Here are some resources for understanding some of the metrics.
In addition the other sites I'll list, Google has some great videos on YouTube about how to understand & use Google Analytics. Tip: before you start diving into your analytics report, take a few moments to watch the flash product demo/tour first.
There are several ways to do a conversation analysis. Some people look at the comment-to-post ratio (are your readers interacting as much as much/more than you are posting). Other look at in-bound links under the logic that if someone is linking to your post/content then it is continuing the conversation on another site. A great site for checking out who is linking to your site is Technorati.
When people come to your site - do they immediately leave? Bounce rate tells you that: it is the percentage of people who come to our site & immediately leave without getting any deeper. You want a low number for bounce rate - in general, a 40% rate is pretty good. Watch the video to learn more.
Who cares about averages -- we should care about distribution. Who are your loyal visitors and what are they doing on your site? Learn about those people who repeatedly visit your site, when the last time the visitor came, how long that person stayed on the site. Go a step further - segment the data (twitter, for example): of those who came via twitter, how long do they stay and how many times have they visited? This will give a better indication as to how "successful" that particular referrer was (& for companies using ads it will help determine where you should keep buying ads & what you should drop). Watch the video to learn more.
Track feed subscriptions
Google Analytics doesn't track how many people are subscribed to your RSS feed. But you still want to know how many read the site through feeds - especially because many times the RSS reader might not ever click through to the site. Google suggests using feedburner to get this information. It will tell you: how many readers, what are feed tools are they using & all sorts of podcast metrics. Tip: set up your feedburner feed before you start marketing your site because if you do it midstream on a blogspot blog then you'll have to change your feed URL (& readers might not take the time to update their subscription to your feed). Watch the video (jump to 11:32, end 15:38) to learn more.
Optimizing your content
Now this one is just really cool: After you've looked over your analytics & you have a good baseline of how your site is doing you might be ready to test ways to improve your site. What if I put a picture of a person with my product on the page? What if I use certain words? Heck, which layout for your site works the best? The Google Web Site Optimizer will let you set up experiments where people randomly get your page with one thing different on it each time - the data (very nicely laid out in a Google'y way btw) tells you what works the best on that page. This is the killer app made simple for usability design, if you ask me. You would use this when you're trying to improve your visitors experience & reach whatever goal you set (like get to a certain page). Watch the video to learn more.
Thinking about search
There are some things that Google Analytics doesn't do ... check out the Google Webmaster Tools. Find out what mobile devices are accessing to your site, the last time Google crawled your site & a little about Google SEO. Watch the video (jump to 7:50, end 11:32) to learn more.
There are more videos, but they are more geared toward making money so I won't go into them but you can view them all in the Conversion University section of the Google YouTube channel.
The key is that reporting is not analyzing -- don't just report numbers, interpret that data & tell people what it means about how people are using the site. Don't just look at one number, understand as much as possible about what is going on in your site. A single metric will not give you what you need to make quality decisions from your analytics reports.