What's the noun for postable? Here's the word you're looking for.
post
(obsolete) Each of a series of men stationed at specific places along a postroad, with responsibility for relaying letters and dispatches of the monarch (and later others) along the route. [16th-17th c.]
(dated) A station, or one of a series of stations, established for the refreshment and accommodation of travellers on some recognized route.
A militarybase; the place at which a soldier or a body of troops is stationed; also, the troops at such a station.
(now historical) Someone who travels express along a set route carrying letters and dispatches; a courier. [from 16th c.]
An organisation for delivering letters, parcels etc., or the service provided by such an organisation. [from 17th c.]
A single delivery of letters; the letters or deliveries that make up a single batch delivered to one person or one address. [from 17th c.]
A message posted in an electronic or Internet forum. [from 20th c.]
(American football) A moderate to deep passingroute in which a receiver runs 10-20 yards from the line of scrimmage straight down the field, then cuts toward the middle of the field (towards the facing goalposts) at a 45-degree angle.
(obsolete) Haste or speed, like that of a messenger or mail carrier.
(obsolete) One who has charge of a station, especially a postal station.
“We met while I was postering for a Thursday night pub nite and we hit it off right away.”
“Well, first we did some illegal bill postering and then we stole some milk crates.”
“That changed last Thursday, when Drury was postering for the Poverty Olympics at the corner of Hastings Street and Caroll Street in Vancouver's Downtown East Side.”