I think it has both positive and negative site.
- Advantages:
+ They (will) study well on websites (such as: OLM; H.vn; duolingo,...)
+ They (will) get more information and news quickly and easy
+ They (will) make more new friends....
- Disadvantages:
+ Can cause some eyes diseases
+ Waste time and money
+ Don't have time to join clubs or have any hobbies (play sports...)