|MetaFilter's site and server can always use upgrades of hardware, software, and bandwidth, as well as more stable funding for continued support of its small but high-skilled moderation and backend team! If you'd like to chip in, you can donate to Metafilter.|
Often in MetaTalk there will be discussion of how posts and comments have recently dropped in quality, and how their quality might be improved again (quality being an arbitrary standard that is sometimes measured via use of profanity, ad hominems, etc). Matt Haughey or Jessamyn will generally delete offending posts or comments, or warn users personally. However, Matt Haughey and Jessamyn are only two people with a limited amount of time apiece, and so many users still regularly find things to complain about in MetaTalk.
A common suggestion that is Matt Haughey should appoint more moderators in addition to Jessamyn and Cortex to help him with the running of the website, but Matt Haughey has consistently disagreed with this. So the primary mode of 'policing' MetaFilter for posts and comments that are deemed bad is simply self policing. That is, members of MetaFilter will, upon seeing a bad post or comment, try to talk to the user in question (usually by posting a thread in MetaTalk) and sort everything out without recourse to Matt Haughey.
Flagging posts and comments to bring them more quickly to Matt Haughey's attention is another, relatively new method of 'policing' which keeps MetaTalk from being overrun with complaints.