Google Sitelinks will always intrigue and excite webmasters until they know exactly how to get them. Google’s official explanation is rather vague and never explains the actual algorithm; still it (and not only it) allows for a number of theories behind sitelinks:
They (sitelinks) serve as shortcuts to help users quickly navigate to the important pages on your site.
I myself consider most of these theories true and logical and think that most likely the combination of the following factors come into play when talking about sitelinks algorithm:
Sitelinks theory 1: Surfers oriented (my favorite one because it has that web 2.0/web 3.0 favor we now want to see in everything):
Sitelinks are given to a site when it “satisfies a great number of people who make that particular query” (mentioned here).
This theory can be considered officially supported by Google:
We only show sitelinks for results when we think they’ll be useful to the user.
What’s more, this theory explains another interesting phenomenon behind sitelinks – they can be geo specific: people from one country may like this website (hence in this country it has sitelinks) while people from other countries don’t like it (hence it doesn’t have sitelinks there). Compare Apple in google.com and Apple in google.co.uk.
Sitelinks theory 2: Domain-authority oriented
The more powerful the domain is (compared to other sites in the same niche), the more likely it will get sitelinks.
This theory is also kind of supported by Googlers – see Susan Moskwa‘s comment:
You’ve probably noticed that most search results don’t show sitelinks; the ones that do are generally for large and/or popular sites. Right now the best advice I can give is to work on increasing the visibility and popularity of your website.
Sitelinks theory 3: Internal-architecture oriented:
If you by your internal architecture managed to clearly show Google what’s important and what’s relevant, you will get sitelinks.
Also mentioned in Google FAQ:
Our systems analyze the link structure of your site to find shortcuts that will save users time and allow them to quickly find the information they’re looking for.
Sitelinks theory 4: On-page SEO oriented:
Many webmasters noticed that some on-page SEO tricks can help in getting sitelinks:
- links located at the top of the source code stand better chance of showing up as sitelinks;
- consistent usage of a keyword in the link anchor text, file path, subpage title and semantic structure (h1 and h2) also helps this keyword appear in sitelinks.
Sitelinks theory 5: Brand-strength oriented
Many people think that Google also evaluates brand-specific searches when considering if your site/ brand is worth sitelinks.
Sitelinks theory 6: Competition oriented
Sitelinks seem to appear in SERPs for those queries for which your site has no (or very little) competition.