tags don’t show up in posts

i’ve never been able to get tags to show up in my posts. i started using a plugin that allows me to make technorati tags (simple tags) a long time ago, but i’ve never been able to get the native tagging feature in WP to work, or at least show up in posts. am i missing something or doing it incorrectly? i was hoping with the 2.5 upgrade, this would fix itself.