I am not sure why 2018 will be the year of privacy coins but I think Monero will increase way too much this year.

Monero was in top 10 coins in the marketcap until last year. Platfrom coins such as Ethereum, Neo, Cardano, Lisk, increased and Monero lost its position. I strongly believe that Monero will take that position again because it has a daily usage. I expecy MoneroV fork will be the accelarator for the increase next month.