Why is “can!!!8217” appearing in posts?

I have just been looking at a few threads and can see versions of “can!!!8217” within posts.

I first saw it in a thread in entitled “budget nightmares” in Budgeting and Bank Accounts and I thought it was something that poster was doing but it is also within another thread called “holding savings for someone” in Savings and Investments.

Entering it into the search box returns lots of results so I am curious to know why it is appearing.