-The ellipsis (...)
-The m-dash (--)
-The period (.)
These are some punctuation marks that many people erroneously use while chatting or communicating online. Andrea Bartz and Brenna Ehrlich (sarcastically and hilariously) talks about them in their article "Watch these 3 annoying online punctuation lapses - CNN.com."
As you may have known, your examiners check for grammatical range and accuracy when they look at your essays in IELTS writing, so it would help browsing through these tips to take advantage of them in your essays.
Go to Watch these 3 annoying online punctuation lapses - CNN.com.