You can either launch Specto from the command line with the command specto or from the Applications >> Accessories menu. Specto will display the notificatios window when launched.
Specto refers to all sites that are monitored as "watches". Before adding watches, click Edit >> Preferences, click Always show the icon in the notification area. You can also set Specto to play a sound when any watch is updated. As well as this you can control the duration for which the pop-up is displayed.
In the notifications window, click the Add button to open the Add a Watch window. If you want to watch a website, Brighthub for example, enter Brighthub in the Name field and choose Website from the Watch Type drop-down list. You can then determine how often Specto should check for updates, using the Refresh Interval. Next, enter the URL of the web page in the URL field and specify the Error Margin. The error margin is important on sites where ads change often, making Specto believe the content has been changed. The default error margin is two percent. An error margin of zero percent makes Specto consider every small change an update. Click Add and Specto will begin monitoring the web page for updates.

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Autostarting Specto is simple. In GNOME, just add the command "specto" in your sessions. With KDE, you can add a shortcut to the auto-start folder.