hi horst nice to meet you you're doing a great job especially if english isn't your first language i'd hate to be editing in anything other than english signing is done when you are editing a 'talk' page when you are having a discussion it really helps to know who said what and when we always encourage people to sign whatever they write there however in articles everything is considered 'common property' we don't sign what we write because we don't want to think that we 'own' it in any way someone might come along and change it later once an article has been in existence for more than a few days there are usually many people who have contributed to it in some cases there may be nothing left of what the first author wrote what a lot of people do is put a list of articles that they have made big contributions to on their own user page that gives you an idea of what a person has done here without claiming 'ownership' i hope you are finding out what you need to know feel free to ask lots of questions wikipedia village pump is useful if you can't find the answer anywhere else or ask me or someone else enjoy your time here mar utc