Trying to figure out an early 2000s fan fiction from Yahoo

I hope this is allowed (there is a flair so that’s a good sign!)

I’m trying to figure out the first long fan fiction I ever read. It was Harry Potter and set after book 4, I was reading it before the 5th book came out.

I don’t remember too much other than it was on a yahoo group, it was super long (pretty sure they did their own finish to year 7), the characters had sex although it wasn’t overly explicit (super shocking at the time for me) and I’m pretty sure Harry learns to be an animagus at some point.

Not much to go on but hopefully there are some suggestions I can look into!