If you want to be sure that email addresses at your organization can be found in these databases, see if the systems administrator has a list of email addresses that can be contributed. That should work for all but the Usenet addresses database. To be found in that one, post something on Usenet. It is not even necessary to take part in one of the newsgroups. Most Web pages are designed for public viewing.
Email addresses tend to be a bit more personal.
The email database providers all address this concern. It is a common question in their FAQs. The companies take steps to limit the number of addresses that can be retrieved from the database to discourage abuse by direct marketing companies. They also state that they do not sell their lists. For the privacy conscious, you can even remove yourself from some of the directories.