How a domain registrar can kill your business
On my previous job we had to manage thousands of customer domains, including annual renewal.
This was very tedious task, so I wrote a Perl script, scraping WHOIS and DNS data for all domains listed on our DNS servers. Based on this data every domain was assigned a status, such as "Ok", "misconfigured", "about to expire", "points to foreign DNS server" or "points to foreign Web server". This script was scheduled to run every other day and sent CSV report (full and diff from previous run) to a person responsible for domain renewal.
Needless to say, our support specialists were very happy with this improvement.