Utah statute requiring sex offenders to register Internet identifiers violates neither First nor Fourth Amendments nor ex post facto clause

Via FourthAmendment.com:

A Utah statute that required that sex offenders register their Internet identifiers with the state violates neither the First nor the Fourth Amendment. As to the Fourth Amendment, there is no high privacy interest in the identifiers that a person uses on the Internet because it is voluntarily provided to third parties. It also does not violate the ex post facto clause. Doe v. Shurtleff, 2010 U.S. App. LEXIS 21988 (10th Cir. October 26, 2010).*