The current software of the forum doesn't allow special characters. So, when there's a character that doesn't find correspondence here, such as € (euro sign), or ‘ (the quotation mark MS Word uses), we get the those symbols.
You probably wrote your post on Word and when you typed ', Word changed it to it's own variant (‘) because of auto-correct.
If you notice the bar stating the date of each post, at the end there will be an icon resembling a pad with a pencil. If you click there, you can edit your post. Granted I'm the moderator, I can edit everyone's post, so I just exchanged the quotation marks and dashes to a acceptable sign.