Intrinsic functions are template variables that are predefined within FeedBlitz, which you can use at any time with no custom fields or tags defined. They are listed in Core Concepts, for completeness they’re listed here:

Subscriber Intrinsic Fields

• <$email$>, <$Recipient$>, <$BlogRecipient$> – the recipient’s email address.
• <$BlogRecipientID$> – the recipient’s ID (aka the subscriber ID) within the FeedBlitz database.
• <$MD5_R$> – lower case MD5 hash of the lowercased email address.
• <$SHA1_R$> – as above, but using the SHA1 algorithm.
• <$SHA256_R$> – as above, but using the SHA256 algorithm.
• <$UID2$> – Normalized hash, see this link.

List Intrinsic Fields

• <$BlogListID$> – The FeedBlitz ID of the list this subscriber and mailing are going to.
• <$BlogOwnerID$> – The FeedBlitz subscriber ID of the list’s owner.
• <$BlogSiteName$> – The name of the site the list is contained by.

Mailing Intrinsic Fields

• <$BlogMailingID$> – The unique ID of this mailing
• <$BlogCycleName$> – The type of this mailing (e.g. “weekly” for a weekly RSS to email campaign).

Note: For transactional mailings, such as test emails and opt-in confirmations, the mailing ID will be associated with a transactional mailing campaign for that day.

Other Intrinsic Fields

• <$DateUTC$> – The date and time in UTC. See shortcodes for formatting attributes.
• <$Date$> – The date and time in US Eastern. See shortcodes for formatting attributes.