Don't spam! Don't block! Most message boards don't allow flagrant advertising, but permit sigtags. Until publishing, make sure you read all laws thoroughly.

Message boards are an excellent way to develop your reputation and become an expert. Contacts on boards can also launch corporate and personal contacts.

Do not email! Do not spam! Do not email! Do not spam! Most boards do not require flagrant advertising but allow sigtags.

There are messaging boards that enable any kind of publicity, but they're not very helpful to network or learn something.