I have wondered what emails sent from smartd would look like. Interestingly, I received such a sample from one of my systems a couple of days ago.

To: hostmaster@[WITHHELD]
Date: Mon, 18 Jun 2012 22:16:22 +0200 (CEST)
Subject: SMART error (SelfTest) detected on host: [WITHHELD]

This email was generated by the smartd daemon running on:

   host name: [WITHHELD]
  DNS domain: [WITHHELD]
  NIS domain: [WITHHELD]

The following warning/error was logged by the smartd daemon:

Device: /dev/ad0, new Self-Test Log error at hour timestamp 2


For details see host's SYSLOG.

You can also use the smartctl utility for further investigation.
No additional email messages about this problem will be sent.

This drive is identified by smartctl as:

=== START OF INFORMATION SECTION ===
Model Family:     Quantum Fireball CR
Device Model:     QUANTUM FIREBALL CR4.3A
Serial Number:    [WITHHELD]
Firmware Version: A5U.1200
User Capacity:    4.310.433.792 bytes [4,31 GB]
Sector Size:      512 bytes logical/physical
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   4
ATA Standard is:  ATA/ATAPI-4 T13 1153D revision 15
Local Time is:    Wed Jun 20 08:26:23 2012 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

This is a very old drive claiming to have been in service for at least 21102 hours equal to about 2.4 years. I guess the counter has experienced a few overflows over time as the drive has been in continuous use for at least 6 years.

SMART Attributes Data Structure revision number: 9
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x0029   100   253   020    Pre-fail  Offline      -       0
  3 Spin_Up_Time            0x0027   084   083   020    Pre-fail  Always       -       2079
  4 Start_Stop_Count        0x0032   098   098   008    Old_age   Always       -       1361
  5 Reallocated_Sector_Ct   0x0033   100   100   020    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000b   100   100   023    Pre-fail  Always       -       0
  9 Power_On_Hours          0x0012   068   068   001    Old_age   Always       -       21102
 11 Calibration_Retry_Count 0x0013   100   100   020    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   098   098   008    Old_age   Always       -       1360
 13 Read_Soft_Error_Rate    0x000b   100   100   023    Pre-fail  Always       -       0
199 UDMA_CRC_Error_Count    0x001a   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0010   100   253   000    Old_age   Offline      -       0

The drive sits in an old system I keep around until it dies completely.