That is a good question. You would be logging into the members area with your email address and your first name will be displayed (not your last name). If your state requires you to report all internet identifiers, then yes, this will likely be considered an internet identifier to them.
I would just report that you log on to NARSOL’s message forum at https://nationalrsol.wildapricot.org/ with your email address that they probably already have on file. They will make a note of it. Most states require you to report this within a number of days, such as 3 business days.
If everyone who participates in this discussion you have going here joins NARSOL to use the forum, you will all have an easier time following the conversation.