The "title, description and tags spidering" switch activates a feature on the Submit Link and Edit Link pages which will automatically pull in information from the web page the submitter gives the URL to, every time they change the URL. The title is taken from the page's <title>, the description from the meta description, and the tags from the meta keywords. If the page cannot be loaded, an alert pops up telling the submitter to check the URL is correct.

The spidered values are only used to fill in blank fields. If the submitter has already typed a title or description, what they typed is retained.