How do I send an HTML email? I use the code in this answer to send emails with SmtpClient, but they're always plain text, so the link in the example message below is not formatted as such.
<p>Welcome to SiteName. To activate your account, visit this URL:
<a href="http://SiteName.com/a?key=1234">http://SiteName.com/a?key=1234</a>.
</p>
How do I enable HTML in the e-mail messages I send?