If you block a sitelink using the new tool in Webmaster Tools, can you still use up the maximum number of sitelinks allocated to you in the search results? The answer to this is no. In short, if you have all 8 sitelinks and you block two sitelinks, you will now have 6 sitelinks. Google will not pick out 2 other links on your site, to make up for the two you blocked.
Last week, Susan Moskwa of the Google Webmaster Central team went to the AMA Search Marketing Conference and had this question asked.
The Q&A, in full text, follows:
Q: If your site only has a few sitelinks and you use the new feature in webmaster tools to block one of those sitelinks, your site will show one less sitelink in search results. But if you have the maximum possible number of sitelinks and you block one of them, will you get a new one to fill its place, or do you just go down to [max-1] sitelinks? A: Every time you block a sitelink, you'll have one less sitelink displayed in search results, regardless of whether you were at the "max" number of sitelinks or not.
As we discussed earlier, you can now see up to 8 sitelinks in action. So if you block one sitelink, you won't be able to add another link to the 8 -- your new max will be 7.
Additional questions and answers are at Google Groups.