This post lists links to various TechNet resources, along with a brief regarding each resource:
Crawled Properties: this page details the properties that are included in the index by default. You can modify the default properties to provide a richer index that is targeted in relation to your objectives.
For example, is a person’s work phone or job title part of the default content that is indexed from MySites? check this page to find out.
to change that, click on Metadata Properties off the Search Service Administration page, available by navigating to Application management > Manage Service Applications
Default iFilters: this page details the file types that are supported by default. And, it lists whether the file types are included in the search administration file types page under the “file type included by default” column. If you don’t see your file type listed, (e.g. adobe acrobat pdf), you have to download and install the iFilter, an image file for the crawl server to use next to pdf’s, and then register the iFilter in registry.
Default connectors: this page explains the various types of connectors that are supported out of the box. Ever wonder what sps3 was for? check out this page.