Honestly, fanfiction.net was my first site to end up writing fanfictions.
The pros of the website is that you can post you fics for free and put anything random on your profile. The cool features they had was highlighting, and copy and paste. But to protect the text and idea's of other people's stories, they disabled the highlighting/ copy and paste. :(
But you can still do that in Mobile version on desktop! XD
So, I had just listed the cons and I was about to go to the pros which is Private Messaging (only if the other user is roleplaying.)
The site has the perfect place to Private Message to another user. Maybe now I use it to only PM users and update my stories very rarely. Depending on what my schedule is. :P
Perfect site for PMing! XD