Any suggestions on keeping hackers out?
Make sure you have a secure Server ... use hard to guess passwords and always different ones. If few other people are administrating WB with you, protect admin folder with .htaccess ... the basic stuff that should be done on any server

Also I posted a question before about if there is a way to have visitors sign up to receive an e-mail news letter and I have not gotten a response. Is that because there isn't a way?
Not without extra modules / applications ...
cheers
Klaus