Postini and SpamTitan are very similar in the way that they filter spam. They both have a message quarantine, the ability to whitelist or blacklist senders, and daily quarantine report emails. There are, however, a few differences that you should be aware of which I've detailed below. Please keep in mind that we offer a full 30 day free trial of SpamTitan email filtering so you can see what it is like with zero risk.

Pricing
Postini accounts were priced at $2.50 each per month. Each Postini account permitted you to filter one email account and five aliases. Some took advantage of the way their system worked and simply used one Postini account to filter 6 total email accounts. This was not their intended functionality, but it worked. The only drawback here was that these 6 users then shared the same quarantine, blacklist, filtering settings, etc.

SpamTitan pricing is a very simple $1.00 per email address per month. An email account counts as one address and a forwarder/alias counts as one address. For example, if you had bob@domain.com setup as an email account and joebob@domain.com setup as a forwarder, you would be paying for two separate licenses for a total of $2.00 per month. Each email address has its own message quarantine, blacklist/whitelist, settings, etc.

Filtered Addresses
With Postini you could selectively filter a portion of a domain's email addresses. With SpamTitan this is not possible. SpamTitan will filter every email address on the domain without exception. Because these addresses are all detected automatically by SpamTitan, you need to make sure that you have your domain's default address (catch-all) set to reject in cPanel otherwise you might be surprised with a larger than expected amount of licenses. Please also keep in mind that Mailman Mailing Lists utilize 11 separate addresses per mailing list.

Filtering Results
The default Postini configuration would result in a lot of legitimate bulk email being quarantined. This would include regular newsletters, announcements, etc. This filtering was actually quite aggressive. SpamTitan doesn't filter out these emails nearly as aggressively. If you find this to be a problem, your best option would be to go through the sender's unsubscription process, which is usually little more than clicking a link at the bottom of the email. Alternatively you can blacklist the sender from your quarantine.