Question regarding emoticons in text/mail

Can anyone tell me, if any recipient can see the emoticons in text messages or mails that I send them from my Windows Phone or Windows Mail app? Or can those emoticons only be properly displayed in certain devices, apps or services that support them, or only on Windows devices? What do those recipients get to see, that can't view the icons?

I assume that those icons are sent in a format that any modern text/mail app can display, but I'm curious to know if anyone has experienced issues with that.

BTW, I'm not talking just about happy and sad smileys, but about the tons of silly icons that you get as suggestions when typing in WP8.1, for example.