Are you familiar with Google snippets? Basically, they are the chunk of information you see under the title of search results. They usually include the URL, a date, history, and most important, a description. In the past, you've been able to define your own description in the metadata of your site, so you had control over what was displayed under your page in results. Now though, Google is changing things so that you may have less control, or at least less direct control of your business's search engine results.  

Late February, Google had another patent granted to them. This one allows them greater flexibility in pulling and arranging snippets for web results. Here is a selection of the patent:

A first set of search results responsive to a first query during a search session is identified. A snippet is identified for each search result related to the first query. The snippet can be selected based on the location the search tokens from the query in the search result. A second set of search results responsive to a second query during a search session is identified. Repetitive search results can be identified.

A second snippet for the repetitive search result is identified. The second snippet can be selected based on the location of the second search tokens in the repetitive search result and the content of the first snippet.

It's a little convoluted, but essentially it's saying that Google may return different description data with your snippet from one search to the next, even if you have defined what you wanted that description to be.

It's strange they are going around what the developer of a site intended, but they seem to mean well by it. The idea is that if you rank highly but don't get clicked, then next time around Google will pull description data from the body of your text and see if that increases your clicks.

Where will they pull from? Like all Google algorithms, the inner workings of this are guarded, but it seems the majority of the time they will pull from the section of the text that contains the words that were searched. There's nothing you can do to change how Google displays your snippets, so your best bet is to make sure your copy is great (like you needed another reason!) and your description data is well defined.

Original post about snippets can be found on Wikimotive's blog titled, "Google Snippets are Going Rogue."