I think the site is famous among the people in this field already, so no introduction is really needed. With the guidance of Daniel from NUS Greyhats, I tried this platform for a week to grind some web challenges.
Unfortunately there is no writeups, simply because I grinded in the PicoCTF Gym for the web challenges only. Also, there is a GREAT source for the writeups, in the Martin Carlisle Youtube channel. I watched the videos for the challenges I failed to solve.
In any case, here is my profile showing the 37 (web) challenges I solved.