Google’s expanded sitelinks give sites greater exposure for branded searches and the ability to dominate the page one results above the fold.
User reactions have been mixed so far (some find them overwhelming or borderline obnoxious) but Google is touting the user benefits and the expanded sitelinks appear to be here to stay.
That means that sites should take advantage of the opportunity to increase clickthroughs to those pages by optimizing their META description tags in a slightly different way.
As can be seen Google typically pulls in about 30-35 characters for each snippet:
This gives new importance to the first several words in the META description tag on those pages. While not a lot of room to work with site owners should ensure that those opening words result in a meaningful snippet.
It is also important to make sure that each of the sitelink pages has a META description tag. MLB and the Chicago Bulls offer examples of what can get pulled in from pages with no META description tag and not much text content: