Go to the site settings (e.g. through the “Settings” button on the plugins page, which will pre-fill the search) and make sure you’ve enabled the plugins.
I have the Akismet key installed. Although I’m not sure how to test it if the plugin’s not working. Also, Akismet is not the only plugin that isn’t working.
I’m running on Digital Ocean droplet, and recently backed up and completely reinstalled the forum as part of the troubleshooting process, so Discourse is up to date.
Can you give some examples of what you’re expecting and what you’re actually seeing? Unfortunately the information we have is a little limited to be able to help effectively.