If you want to originate mail from your site that uses a sender address in a domain name of yours, to help prevent your messages from being marked as spam, you should publish an SPF record incorporating our sending servers. This can be easily done without the need to check for periodic updates by using the SPF include facility. Just add include:sites.nearlyfreespeech.net to your SPF record.
For example, if you send email from your site, such as forum registrations from firstname.lastname@example.org, but most of example.com's email is handled by Google apps, you would add a TXT record for example.com like:
v=spf1 include:_spf.google.com include:sites.nearlyfreespeech.net ~all
This will tell the world that mail from example.com may originate from either Google or our sending servers, and that anything that comes from elsewhere is probably (but not definitely) a forgery.
Because of the very different usages and sending profiles, we have three completely different sets of email servers: one for NearlyFreeSpeech.NET service-related email, another for email forwarding, and a third for mail originating from member sites. Thus it is very important that you do not put include:nearlyfreespeech.net in your SPF record. We also strongly recommend against hardcoding specific servers into your SPF records. We may change them from time to time without notice.