IADB2 Aggregate Score Values IADB2 uses the same data as contained in IADB, however it provides a different style of response based on that data. IADB returns the typical "A record" type responses usually associated with a DNS list, often returning several individual record responses for a single listee, each signifying a different piece of data. For example, 127.0.1.255 means that the listing is a vouched* listing, and 127.2.255.1 means that the listee publishes an SPF record. (*A vouched listing means that you are either personally known to ISIPP or a referring group, or that your reference and background check and mailing practices demonstrate that you are someone to whom we would refer others for services.) IADB2, on the other hand, returns an aggregate weighted score in the form of a single 'A record'. Looking up an IADB listee who is a vouched listee, and who publishes an SPF record, in IADB2 will yield a single response of "127.0.0.30". This indicates that the listee has several data points in IADB which, when aggregated, yield an aggregate IADB2 score of "30" in the last octet, with 10 being the default, and signifying only that the site is listed in IADB. This unique aggregate scoring system allows certain receiving sites to make email acceptance, delivery, and processing decisions based on setting an IADB2 score threshold of their choosing. For example, some sites may choose to say "if a site is listed in IADB, and has an IADB2 aggregate score greater than X (for the last octet), their email should be accepted and delivered", or "if a site is listed in IADB, and has an IADB2 aggregate score of between Y and X, their email should be accepted but we should probably still do a lookup at some of the DNS blocklists". The following is a list of the data collated by IADB, and the points assigned to the data only for purposes of the unique IADB2 aggregate scoring system: Data *Explanation Points Listed in IADB *Default score 10 Vouched listing *They are known to ISIPP as good senders 10 Participate in EDDB *They have certain required policies and are immediately    contactable 10 Is a member of EPIA *They participate in a cross-industry sender/receiver forum 10 Publishes SPF, Microsoft Sender I.D., Domain Keys and/or rDNS *They take responsibility for domain authentication 10 Participates in Habeas or Bonded Sender *They are contractually obligated to send only wanted email 20 All mailing list mail is opt-in 10 All mailing list mail is confirmed (double) opt-in 20 Only one-to-one and transactional email is sent, no bulk mail is   sent at all 20 Note that not all scores are the same, and not every data point about a listee will result in additional IADB2 score points. For example, a listee who publishes SPF or Microsoft Sender I.D. records will get 10 points whether they publish one, the other, or both. Similarly, a listee who participates both in the Habeas program and the Bonded Sender program will get 20 points whether they participate in one or both. The point system has been weighted to give receiving systems the most useful result with a single IADB2 lookup. We have found that IADB2 scores of 127.0.0.30 and above tend to be the most useful for helping a receiver in making further email delivery and processing decisions.