Marty Eigner: Instead of demoting the sitelink every 90 days, is there a way to make it permanent?
Edwin Jonk: Not really but you can give Googlebot signals that a particular page is more important. For example, links to your internal pages directly from the home page or the URL-structure like example.com/category/about-us versus example.com/about-us.
Ping +Arthur Radulescu ;because I know you will rock at this question.
Marty Eigner: Its a pdf of an outdated product so I am not sure why Google has chosen it.
Arthur Radulescu: Hi +Marty Eigner, Google has an automated algo which choose sitelinks. Probably, it sees that particular pdf as being relevant for your most common ranking keyword and therefore it emphasis it in search results by showing it as a sitelink. +Edwin Jonk ;is right, the max. demote time is 90 days. If you demote a link, Google pick up the signal as that specific URL is not beneficial and usually, It won't show it again as a sitelink after those 90 days pass. In the meantime, followup on Google search results and if you're not satisfied with the sitelinks showed, the only way you can influence that is an indirect measure - is to adjust your internal website linking structure - to increase internal links pointing to a certain section/page to be seen as such by Google. This is a complex process, takes time for Google to notice, and I suggest you do this only if you know what you are doing, as you can hurt your rankings by doing this. It's easier to demote what you don't like and leave Google to pick up new sitelinks instead.
Marty Eigner: +Arthur Radulescu Thanks for the advice. What I will do is wait what Google does after the 90 days because I have seen examples of what you are saying and Google may continue not to show it. If worse comes to worst I will have to increase the importance of another page through the process you have outlined.
I have just demoted a sitelink in Google Webmaster Tools and it says "Effective until May 22, 2015". What exactly does that mean? 
