Welcome to the world of Site Content. There are a whole host of content you can place these days. During the Mosaic infancy, the only thing you could possibly install on you site were some clipart, a javascript clock, and the default 468 x 60 banner for web advertisements. Times have changed now as content is more dynamic and broader.
Here are 3 examples.

Integrated Dynamic Content

A lot of sites will use the Google Maps API to place maps on their site. You will notice some sites will registered users will try and display the location of their users. Of course, they dont really know where they are but this is based on the information the user has provided when registered on such websites.

These sites use Google Maps for integrate into their tools.
Longitude, Latitude Popup
EarthTools

Design Content

Other Sites are adding flashy icons which are converted from OSX and Windows desktop icons. These icons sometimes free for personal websites and are fee-based for commercial sites. Some have redistribution licenses as well.

Popular sites are:
Interface Lift
Icon Factory

Widget Content

This slow revolution is picking up as publishers want more fancy content and also want their website to look like a OSX Dashboard, Yahoo Widgets, or Konfabulator

A great widget is this 24-style widget that mimics the countdown clock from the popular tv show.