Send-MailMessage has been around for many years. It can be used to quickly send an email without the need to have an email client at hand. All you need is an SMTP server. Likewise, it can be used to diagnose problems with a particular mail server:
Send-MailMessage -SmtpServer 'mail.yourcompany.com' -To 'SomeAccount' -From 'SenderName' -Subject 'Hello!'