It is a web platform, but also a mobile app which has many functions for learning a language. However the most important and the only one reason why we should use it is for reading in other language. It was created by popular polyglot Steven Kaufmann.
Using LingQ in comparison to book or e-book is that it is built in translator (various ones), so if you encounter a word which you do not know, by one click on it, you will get instant translation which will speed up the process of reading rapidly. Also, by encountering a new word (blue), you can save it as known word (white) or as the word that you do not know yet (yellow).
This is an example of using the app. When I open new lesson (text), I automatically see new (blue), not known yet (yellow) and known (white) words inmediatelly. As I go through the text (reading) I mark every blue word as known or not known yet. Then I go to the next page etc.
When I read and see a yellow word, I stop and think: do I know this word? Or still not? If yes then I mark it closer to know word (from 1-5) before completely mark it as known. It may sound complicated, but it is pretty straightforward.
If I do not know some word I simply click on it (or on the whole phrase) and get the translation right away.
The app saves the words so you can track your progress. You can also review your yellow words as flashcards.
The great thing about the app is that you can import your own materials (texts, articles from internet, etc.)
From the beginning it may seem complicated, I recommend to check this tutorial until the end to be able to imagine how it works.
I will also mention that is paid app, but you will benefit from its great features. You can however try it for free with some limits.
If you would like to try it and at the same time support my work, use my affiliate link to get extra 100 possible word creation in free version. Thank you!