Because I use YahooGroups as the primary archive for current and old jobs I am at their whim for security features. Which honestly is really a good thing since they have millions to spend on safeguarding accounts. One "feature" that is in place is email masking. When a job is sent in to the ShovelBums list and sent out to the 16,600+ members and the message includes a contact email any recipient of that email can read the entire message, including the contact email. The message is also simultaneously stored and cataloged on YahooGroups. If you are a member of the ShovelBums list and are signed into YahooGroups.com and you go to view the message in the archive you can see the complete message, including the email address. BUT if you are not signed into YahooGroups and a member of the ShovelBums distribution list you can still view the job posting, because they are publicly available, but you will NOT be able to see the email address because YahooGroups obfuscates it to prevent spam harvesters from skimming every public forum.
I recognize this is a PIA. Seriously. But the only option I have would be to make the group private, which would force you to set up an account on YahooGroups to view any of the messages including the email address (which for some of you though would be a bigger PIA and my goal is to make your life easy and get you a job). So I have left the viewing of the jobs "public" with the expectation that with 16,600 members on here for sure you know someone who gets the emails and you can ask them :-) It's a small field and because of our training we are all resourceful. I know its a pain, really I do, but it is for the greater good.
Alternatively, just join the list :-) (there is a handy digest mode that concatenates all the days jobs into a single email) and you can see the address.