Can someone show me how to see how many contacts are in a Distribution List?
At the moment the Distribution List just shows the name and email address.
The simplest way I've found is to Export / Save As your Distribution List / Contact Group as a text file, and use a text editor such as Notepad++ to see the line count:
Alternatively, this site here has a macro you can download and run on a distribution list to return the count.
There is a free Email Address Report available that shows the total number of addresses. Just select the required distribution lists and make sure to set the "Expand address groups" option.
If you want to count the number of email addresses in an Exchange distribution list you can use PowerShell.
add-pssnapin Microsoft.Exchange.Management.PowerShell.E2010
$distributionlist = (Get-ADGroupMember -Recursive "*Name of Distribution List*")
$distributionlist.Count
If you want to count the number of email addresses in an Outlook distribution list Jonno's answer will do what you are trying to do.