mrilu -mri- gismu

x1 mails/posts [transfer via intermediary service] x2 to recipient address x3 from mailbox/post office/sender address x4 by carrier/network/system x5.

Also x4 post office, mailbox. (cf. benji [in which the medium need not be a 3rd party service/system, and x2 need not consist of discrete units], notci, xatra, tcana)

In notes:

x1 transfers/sends/transmits x2 to receiver x3 from transmitter/origin x4 via means/medium x5.
x1 is a message/notice/memorandum about subject x2 from author x3 to intended audience x4.
x1 is a station/node of/in/on transport/communication/distribution system/network x2.
x1 is a letter/missive/[note] to intended audience x2 from author/originator x3 with content x4.
b1 distributes b2 to b3 from b4 over path b5. b1 is a distributor.
x1=b1 is a post office of post clerk x2=b2 at location x3=b3 for mailing system x4=m5.
l1 is a mailing list with subscribers/recipients l2=m3.
m1 (agent) sends e-mail m2 to person / computer m3 from person / computer m4 by computer network m5.
be3=bi1 signs up / subscribes to be1 for publication be2 from be4 by means be5.
x1 is a document used to prepay service x2 like postage costs, tax, license fees; x1 is a postage stamp used to pay service x2