As with most questions, there are two sides to this.
In her blog, Victoria Strauss argues “there’s no need to register your copyright prior to publication.”
But she gives no ‘down-side’, other than you might be solicited a lot.
Note that if you copyright using the US Patent office’s website, you can give one set of contact info for the copyright office, and one for public access (solicitors). Nothing says you have to give actual info to the public access. I gave the patent office my primary email but I used backup email address for public access so junk mail would be less annoying.
Read her full blog HERE.
While ALL posts and articles I found touted that your work is copyrighted the instant it is typed, almost all stated that you have a better chance in court (if it comes to that) if you registered your work with the patent office.
Here are some of the articles PRO, or at least neutral…
And of course, here’s the link to the U. S. Electronic Copyright Office.
It only costs $55, but it takes 6-8 months.
Don’t worry though, your copyright is effective the day you submit, not the day the finally stamp it.
That’s assuming someone didn’t copyright your work yesterday