As of Lucatec® Mask 5.0.3 the following signature macros are available:

$$USERDISPLAYNAME$$
The display name of the current user
$$USERSMTPADDRESS$$
The e-mail address of the current user
$$SENDERDISPLAYNAME$$
The display name of the automatically determined sender
$$SENDERSMTPADDRESS$$
The e-mail address of the automatically determined sender
$$USERDISPLAYNAMEREV$$, $$SENDERDISPLAYNAMEREV$$
As above, but name elements will be shown in reverse order, thus allowing you to turn a display name of "Doe, John T." into "John T. Doe".
$$INCLUDE:"FileName"$$
The contents of the specified file. The fully-qualified file name may include environment variables such as %ALLUSERSPROFILE%, %HOMESHARE% or %TEMP%.
Note that the quotes around the file name are mandatory and may not be omitted even when the file name does not contain spaces!
$$SIG:"SigName"$$
The contents of the specified (local) signature, thus allowing you to combine multiple signatures.

Furthermore, the following macros are available for making queries to the Active Directory (depending on how you've set up authentication these might not work in Hosted Exchange / Office 365 environments) :

$$UserDetail:attributeName$$
The value of the specified AD attribute for the current user
$$SenderDetail:attributeName$$
The value of the specified AD attribute for the automatically determined sender

To find out the names of the various AD attributes, look for them on the "Attribute Editor" tab of the user's Properties dialog. For example the attribute name for job title would simply be "title", i.e. the full macro would have to be $$UserDetail:title$$.

All macros except the ones beginning with SENDER or Sender can also be used as so-called “Expand-on-sync” macros by using §§ instead of $$ as the delimiter. Doing so will cause the macros to be expanded not when the signature gets inserted into the message but rather when it is copied into the local user profile via the External Signature Synchronisation feature.