On my system (debian) and on Dreamhost, I ended up with a ton of mail
when I did that… Curl sends back a response report to cron which sends
it to your mail drop.
So even though the output is suppressed, the report isn’t.
Easy fix:
0-59/5 * * * * curl -s -r 0-99 http://somedomain.com>/dev/null
/dev/null