NPM

The term NPM stands for new page master (sometimes written as mastah) and it is mostly know to Slovenian users of the interwebs. A user is a new page master when his or her post is the first post of a new page in any given thread. There are 2 kinds of NPM's: one is intentional where a user will usually post a post containing only these three letters. It often happens that a lot of people go for the NPM which often results in epic fail.
The other kind of NPM is a spontaneous NPM where a user simply replies to a thread without knowing his or her post will the first post of a new page. These posts are usually edited after the user has realised he/she is a new page master with a phrase NPM confirms, which means that the fact he is a NPM what he has written is completely true.

The meme was started at a Slovenian board Joker mn3njalnik and soon gained popularity across other Slovenian boards. Due to language limitations it hasn't reached international popularity yet.

See Urban Dictionary entry: https://www.urbandictionary.com/define.php?term=npm