We have implemented Open SPF for the domain Soulreaper.net, which means that every email that goes out from the mail-server belonging to us gets a tag on it which says “mailed-by: soulreaper.net” and you should also see “Received-SPF: pass” if you look at the mail-header. This example is valid if you’re using Gmail. You should be able to see the same header-information in any mail-provider that checks SPF-records for incoming email.
If you use Hotmail and previously were seeing the notification-emails go into the spam-folder you’ll probably see more emails being directed to the inbox as the mail-servers at Hotmail can see that it is really “us” sending the emails and no-one else. (Hotmail and some other mail-providers think that anyone sending over a certain number of emails per day or even per hour without a SPF-record is a potential spammer, thus all emails go into the spam-folder without asking.)
In other words, adding a SPF-record means a higher reliability for all email originating from the site reaching you.
If you’re interested in reading up on the Open SPF-standard you can check the project’s webpage @ http://www.openspf.org.
Open SPF stands for “Open Sender Policy Framework”.