First of all, please note that what I am going to write is just tips for safe and fun intercation. My intention is NOT to discreminate or blame on particular people.
If you got a message in English, be careful with scam trying to persuade you to send money via Western Union Bank. Just ignore and block them if such words as "US solider" "United Nation" "Refugee" "Nurse in Africa" "Widow with a cancer" etc. are mentioned.
If you look for off-line friends to hang out or to practice conversation, be careful with guys who contact you telling you false gender. Their purpose is sexual relationship. Thay may insult you once you turned the relationship down or block them.