Some CivicSpace modules, such as search, notify and aggregator, have periodic tasks that must be triggered by the script cron.php included with your CivicSpace installation. You can do this manually in your browser by visiting your cron URL page (a blank page will display once the cron tasks have been executed).
However, the better way to do this is to have cron.php executed automatically using the Linux/UNIX crontab function.
0 * * * * wget -O - -q http://www.example.com/cron.php
00 * * * * /home/www/drupal/scripts/cron-lynx.sh
Alternatively, Drupal has a poormanscron module available for download. However, this module is much less efficient in terms of system resources compared to the methods described above. The poormanscron module checks to see if cron needs to run every single time a page is viewed on the site.