Generally digital citizenship is to teach users the rules of good citizenship online. This usually includes email ettiquette, protecting private information, staying safe online, and how to deal with bullying, whether you're a target or a bystander. Digital citizenship at a Kindergarten level is extremely cructial to educate properly. Usually this is the age where children are just getting online to play games and explore so setting rules or regulations may be a bright idea.
To me it's important to educate young students about digital citizenship due to the materials that can be reached while exploring online. Especially at a kindergarten stage where a child may just be 'click happy' and could lead to almost anything. There are man dangers that can be confronted while online so educating students on safety and proper usage of technology is a must!
Some teachers may want to look into setting restrictions and locks on computers that allow internet access. This resource would promote digital citizenship to such a young range of students.