When a new link is added to an Internet page that refers to your site you want to know about it as soon as possible. It will indicate which pages people are finding useful on your site. If the link is one you have paid for you will want to check that the information describing your site has been added correctly. Most links will have a short lifetime if they are on a news or listing site and so it isn't appropriate to wait until a routine weekly scan of the log files.
Site Vigil will raise an alert as soon as the web site traffic hits a new sudden peak or when a new source of referrals is identified.
For example the following Site Vigil alert indicates that a new web site is making referrals to the site and should be checked out :
* Alert* Silurian : 2 new referrals http://www.hinweb.com/showpic.asp