When transacting, always be vigilant and skeptic because you'll never know if the site or person you are transacting with is still the same site or person before. Always secure your transactions and always check the sites if it is the correct URL because just a little tweak of the site may deceive your eyes not noticing that it is a phishing site. With so many airdrops and ICOs nowadays, there are some that requires a wallet download and maybe that wallet has a virus to get your data and you end up with nothing the next time you check your funds. As for investment, I would not invest to a HYIP site because I have been scam a lot of times before being a newbie so I learned my lesson well.