Well practically anything.. Just like Joomla's smart search is scalable to any extension by writing plugins, our extension will also allow developers to extend it by writing their own plugins to help us index their data to enable advanced search for it. As of now, we have basic plugins for Joomla content, Seblod, Zoo, JomSocial & Community Builder. These can be easily extended as needed.
The Admin needs to create & configure a "Search Indexer" for the extensions which Advanced Search supports. The Indexer uses the extension specific plugin to build a search index that will allow us to give a nice advanced search interface for that extension on the frontend. Each indexer can be configured where you can select content types, fields etc that you want to make searchable in advanced seach.
A SocialAds like mapping interface lets you chose how to treat various fields in the Advanced search system from a choice of text, range, single or multiselect fields.Once the indexer is created, you can fill up the index by running the cron job. The Cron will also take care of keeping the index up to date.