So, I've been around on the Internet for quite awhile now, and over that time I've accumulated a lot of identities? Why you ask? Well people change over time really and I think some identities didn't suit me. I tended to explore aspects of my personality by making up a new identity and playing the role. Really it was sort of like Table Top Role Playing but online.
So here's my recommendation on how to go about structuring your online identity(ies). First you've got the Legal Identity: Make an email account/social whatever use your first and last name number on the end (thanks hotmail for that standard!). Use this for resumes and the dreaded facebook etc.
Pseudo Identity: This is your secondary identity and where you can keep your personality that you just aren't comfortable with displaying away from the keyboard and also grow as a person.
Random Identities: Exactly what it means, these are completely random identities that you never link with your first two identities. These allow you to enter shadey and possibly unsafe places on the Internet without putting yourself in danger. You can throw them away as needed and forget they ever existed. Anonymising technology is generally must to use with them.
Over time I've found this to work the best it allows me to not be recalling tons of identites while keeping me safe in almost all situations. Happy Cybering! (tehehe).