As a IT student I use and recommend this website to all my friends.
It has a wide variety of solutions and explanations for every topic in IT industry.
The best part is it also provides GATE questions to practice.
If you are a tech enthusiast who knows about topics and feel like you can explain about any topic then feel free to write and explain on this website it allows you to explain yourself if know better.
Overall great for CS and IT students, and those who are in this field.