A question I hear a lot is why don't the Sitelinks I see in a Google search result, match what I see when I login to Google Webmaster Tools?
For example, here are the Sitelinks I see for a search at Google.com for search engine roundtable:
Then, when I login to Google Webmaster Tools and click on "Links" then "Sitelinks," I see a slightly different set of Sitelinks:
In search results, the sitelinks displayed are determined algorithmically based on the user's query. So, while Webmaster Tools may show 8 sitelinks for your verified site, it's possible that search results show only a subset (e.g. search results display 4 sitelinks). Furthermore, the sitelinks displayed in search results can vary according to the query (e.g. different combinations of sitelinks for different queries).
This is similar to how Google shows your snippet in the search results and even the title in the search results. So showing a dynamic Sitelink set, based on a query, does make the most sense.
Some other useful Sitelink Q&A:
- Sitelinks are displayed based on 1) a relevant structure for your site conducive to sitelinks, and 2) that sitelinks will be helpful for the user's query.
- New Sitelinks are not immediately available after you block an old Sitelink.
- Every time you visit the Sitelinks page in Webmaster Tools, whether or not you modify your Sitelinks settings, the blocked sitelinks will renew their blocked time for an additional 90 days.
- Your site must have at least 3 unblocked sitelinks in order for your sitelinks to appear in search results.
Forum discussion at Google Groups.