The spider plugin will collect information from specific sites that you specify url to. It collects both meta description and data for each page on that site.

You can also give the spider some keywords to work with. Ex: only collect pages with the words "health", "doctor" and "medical" in them.

The spider then comes up with a list of links in a separate spider-database. You can choose to validate these links before they are added to the spider-database, or they can go directly in. If you want to, you can also integrate these links with your ordinary links-database.

When searching, if there are no hits from the ordinary links search, the spider database will be searched. You can also search only the spider-database if you want to.