Angie's Diary is an online magazine. That is the short and simple answer.
There is much more to it than that. In truth, I do not know all there is to know about Angie's. What I can tell you is that the mastermind behind it is really a mistress-mind.
Angie has a real woman behind it - unless it is a man with a complex artificial presentation of a mysterious person who is known as 'the Angie behind Angie's Diary'. Either it is that, or a real woman. I think Angelica is a real and ordinary but amazing woman rather than a man's trick or a transgendered woman or womanesque type of being.
The magazine is a bit complicated, more so than I understand. In this case, luckily, I don't think my ignorance is caused purely by stupidity or brain damage.
For all this and more, Angie's Diary is a great invention and wonderful discovery for so many early in the 21st century.