Utah's database of convicted sex offenders is, for the most part, considered a good thing. It is important for information like that to be available... especially where children are concerned. There are two big issues that some might see as potential ethical problems though.
First, the site doesn't give us the whole story. I've heard people talk about this problem before, and they have mentioned that a big problem is that it makes some people look like horrible people when they are not. An example that i have often heard is when an 18-year-old is dating a 17-year-old and they break up. The 17-year-old gets mad, reports the 18-year-old, and suddenly, they have a criminal record as a sex offender. Now, I know this is not the case with a lot of the people on the database, but it isn't really fair to those few people who really do have situations like this.
The second is that it prevents these people from moving on with their lives. It haunts them in their jobs, relationships, and even where they make their homes. Society doesn't really give them a chance to be "rehabilitated" and rejoin the community. I think this is unfair to some of the people, like the ones I mentioned above. At the same time though, there are a lot of people who deserve to be haunted forver by the things they've done. So this is an idea that is also kind of up in the air for me.
Overall, I think the sex offender database is a good idea with good intentions, but like all good ideas and intentions, there are always going to be some problems.