Advanced Segments are very useful for comparing different user streams and illustrating them with graphs. You can find a good explanation how you can create this segments with Google Analytics at the official Google Analytics Blog. The following questions you should always answer in your traffic stream analysis:
Which traffic sources send the “happiest” users?
Sure, you know your most important traffic sources, but do you also know which source sends the happiest users? With Advanced Segments this can be very easily be visualized: Just create a segment [source] (matches exactly) [referring site] for each source site that you want to compare and select for example “pages/visit” as metric in the report. This is a very effective way to figure out at which kind of websites you should try to get links/advertisement and where better not!
How is the site performing with different browsers and screen resolutions?
Is your site performing good with small screen resolutions and are they browser safe? For the case you see significantly worse values for Internet Explorer 6 than you should better test it again, because Internet Explorer 6 is well known for Browser bugs. The segments for browser and screen resolution you can find in the systems folder.
How are the pages performing as landing pages?
According to Google Analytics a landing page is defined:
Landing Page: The pages where visitors first reached your site
Pay special attention to first reached! This detail can have a huge influence, because a page that in general performs well does perhaps perform poor with users that first reached your site through this page. The best would be if you add to this segment also the AND-constraint [New visitors]. That way you can see see how users react that have first contact with your website through the inspected page.
How are the most important pages performing?
Actually this is a very obvious point and you can find a nice example for this at the Google Analytics blog
Is there a different behaviour of users from different countries?
Especially websites in English or Spanish language will very likely have high traffic numbers from lots of different countries and the usability values for each country can be different. For example cultural factors or the general status of Internet knowledge can influence the user behavior.
There are much more possibilities to analyze websites with the Advanced Segments, especially creating segments with multiple constraints can deliver with some practice very useful results. Please let me know about your experience with Advanced Segments. Which segments do you use?