I run multiple Drupal sites. These mainly use the same code base, but I still use links for files and directories in Drupal so I have flexibility.
Some advantages are:
Drupal's core aggregator is not the best. I recently started looking at the list of Drupal module aggregators available to try and find out which one was the best and most likely to be updated.
In particular, I was interesting in being able to create feed items as normal Drupal nodes instead of the specialized aggregator items.
I noticed recently that my cron.php setup was not working anymore on my Drupal websites.
Cron.php had not been called in a very long time and this turned out to be because lynx was not available from the Jailshell with my web hosting provider. wget did not work either and the curl script did not have access to the curl executable.
I started looking for an alternative and found a useful comment on the trusty Drupal site at this page
The solution is to use Perl. Perl worked great, so now I have something like the following Perl script called by my crontab process.
I tried various methods of integrating Adsense code into my Drupal installations.
I used the 'footer' section in the 'settings' area of Drupal. This allows the display of adverts down the bottom of the page.
I also tried using blocks. Blocks were useful because they provide functionality for hiding themselves. You are not meant to show Google Adsense on pages like user registration.
These two approaches meant pasting Google Adsense code into each Drupal installation via its web interface. Google Adsense code doesn't change often though, so it isn't such a bad thing.
I also tried hacking around in the Drupal theme templates to place my Google Adsense where I wanted.