If you have any reason to communicate with your site owners, this script might be handy.

A few uses could be:

• Communicate policy changes as they relate to SharePoint Site Owners
• Communicate outage notifications to your site owners
• Communicate upcoming training opportunities to your site owners.

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

$logfile = "c:\temp\SPOwnerEmailList_$(get-date -format `"yyyymmdd_hhmmtt`").txt"

$webapp = get-spwebapplication http://yourURL.com
$sites = $webapp.sites
$email = @("") #this sets up an empty array
foreach ($site in $sites)
{
   $weblist = $site.allwebs
   foreach ($web in $weblist)
   {
      $owners = $web.associatedownergroup
      foreach ($owner in $owners.users)
	  {
	     write-host "$($owner.email)  - $($web.AssociatedOwnerGroup.Name)"
	     $email = $email + $owner.email.ToLower() #this add's the current email address to the array
	  } 
	$web.dispose()	  
   } 
   $site.dispose()
}

#Sort the array and remove duplicates:
$email = $email | select -uniq | sort

foreach ($m in $email)
{
	"$m;" | out-file -filepath $logfile -append
}

#this just outputs how many email addresses there were to the screen:
$email | measure

The script creates a text file and it’s fairly easy to copy-> paste the results to Outlook.