Usually I see sites with sitelinks have some kind of authority. Though google states it does not.. Lets take an example.. Johnchow.com get penalizes by google it not only loses the pagerank but also sitelinks.. If authority and sitelinks are not related then it should have never happened.
This is only my personal opinion but i dont associate sitelinks with authority. I have one website that has sitelinks, what i do think it represents is trust and reputation although thats questionable too as ive seen: Warez sites with sitelinks Major link sellers with sitelinks You get the idea. But ive noticed sites with sitelinks having extentions to the main part of the site so maybe: site with attached forum site with attached blog site with attached blog and gallery site with attached classified and directory But i think its down to constant traffic too. I know of a site thats lost its pr but kept its sitelinks.
we did a post about this a little while back. I wont link to it but you can find it near the top of this search sitelinks authority DP is at the bottom of the page
Authority is such a subjective word. A year or two ago it more referred to the hub type websites that linked to a lot of the top quality sites in a niche, had plenty of unique content about that niche and it usually had good rankings itself. Links from these types of websites were thought to be of much greater value than other links. These days many people are throwing that word around while discussing sitelinks. Really there are many factors that go into awarding a website sitelinks. So it is tough to say it comes down to authority. The argument that could be made is that most websites in the top 3 should then have sitelinks if it just came down to authority. It is likely a combination of many factors including relevancy for that keyword. So it is easy to jump to the conclusion that this must mean authority. It does signify some level of authority...but just for that keyword and not necessarily for that entire niche.
yea keyword authority I'd go with. and dependent on geo location and / or the particular Google index too