Component that allows your website visitors/members to recommend your site to their friends.
Joomla sitemap component – Joomap
Joomap is a sitemap component for Joomla! that shows the normal Menu Structure, Content Categories, Sections and Virtuemart Categories in a hierarchical list. A plugin system and translation support make it easy to expand the range of supported content and localization! The new version also supports the generation of a Google Sitemaps conformant XM
Reciprocal link exchange component – Linx
An easy to use component for managing a reciprocal link directory. Visitors to your site can submit their link, but only after adding a link to your site first (automatic check). Allows categorization of links. Full administration to maintain links and categories.