what??? Thus, simple explanation on site links would be, popular pages on an old domain those have got links to them in top level navigation of site...of course you never know what Google sees as popular and important...also there can be a debate about old domain theory Yes, they come and go...happens to couple of my site quite often
"Sitelinks are links to a site's interior pages. Not all sites have sitelinks. Google generates these links automatically," If you set up your linking structure correctly maybe this will also help you get sitelinks.
Google rates sitelinks according to how highly rated your link is. So the best way to do this is build good content that is frequently visited, ensure you update your content regularly and get links from sites with good pr