This is the 4243rd most frequent Swedish word.
skriven
"Written."
The word 'skriven' is part of the verb 'skriva' standing as its past participle form (skrivit), expressing the completed action of writing.
Jag har skrivit ett brev.
I have written a letter.
Here, 'skriven' is used as an adjective derived from the past participle, describing the state of the text as having been written.
Texten är skriven av en känd författare.
The text is written by a famous author.
In this case, 'skriven' is used to show the passive voice in the past tense, indicating that the message on the board had the action of writing performed on it.