Just starting to get my feet wet on domain authentication, and I've sure I've only scratched the surface of the info out there.
Our current host does not support DomainKeys, however, I was able to validate the Sender ID.
It seems that more than a few hosting companies do not support DomainKeys (ours says "Unfortunately our DNS only supports one SPF record. You would need to switch to a third party provider for support of TXT records.") - so I guess I'm asking for an educated guess on how important this is, currently, and how important it will become in the future? We're happy with our hosting, and do not want to switch completely/haven't yet found a quality, comparable service that offers support of TXT records.
Any opinions/ideas? Anyone have hard data on how many bounces you've had with and without DomainKeys?
No need to switch your web host, just switch DNS providers. Use someone like ZoneEdit (http://www.zoneedit.com) and you can have as many TXT records as you want and it's free for up to 5 zones. I've been using them for years and have had 30-40 zones with them at any given time.
An added benefit of breaking up the services your web hosting environment needs (ie: host, DNS, registrar, etc.) is that you get some flexibility in how transfers take place if you ever need to replace one of those providers for any reason.
I've just posted about this on the blog at http://www.campaignmonitor.com/blog/archives/2008/01/more_answers_about_domainkeys.html
It's tough to put a specific number on the benefit of DomainKeys, because the email is still sent but may go through additional filters, and even if it fails might not necessarily be bounced back.
However, it is clear that more systems will be preferring authenticated email in the future, so aogenoff's suggestion of a separate DNS host is a good one.