Web pages have long included anchor links, which, when clicked, send you to a specific section of the page. Wikipedia uses them heavily to help users jump between headings and navigate the sometimes large articles more efficiently. Google has announced that it is now including these anchor links in search results. This is right in line with Google's mission of helping users to find the information that they are looking for as quickly and accurately as possible.
For an example of how this works, try searching for "nuclear fusion." As you can see, Google pulls out the headings in the article, so if I was really interested in the requirements for nuclear fusion, I could jump straight there. This is a great addition and really helps in cases where you are dealing with long, text-heavy pages.
If you are a Webmaster and want to set up your Web pages to identify sections to Google, then read this post on Google's Webmaster Central to get you started.