Some Usenet Newsreaders in the Unix world have tried to make it easier to find interesting postings and filter useless ones. To accomplish this, these newsreaders provide so called "score files", which are simple rules that, when triggered, alter the rating (score) of a post. For example, any post by author "Donald Knuth" might be automatically scored high, whereas one by "script kiddie" might be scored lower. Sometimes different rules fire for an individual post, making an otherwise hidden post visible or vice versa. The scores can then be used to sort the posts or to even delete all posts below a certain threshold.
In spite of their usefulness, scorefiles are an individual undertaking. Some users post their scorefiles regularly, but this is the exception: typically this data is not openly shared and collaborated on. Otherwise, the rampant spam problem hurting the usefulness of the newsgroups might already be solved.