I have some content that I can add all of the time to fit my site's theme but it's not something I want to heavily promote. Is there anyway in wordpress to make new posts that only appear in their category page, but not on the main page?
Yeah but these are posts and will be added several times a day, pages can't handle it. There must be a way to make posts that only appear in their categories?
pages can handle it However, if you don't want them to appear on the home page, you can exclude some categories from the loop in the index.php file. Check the link below : http://codex.wordpress.org/The_Loop#Exclude_Posts_From_Some_Category
Use "Advanced Category Excluder" plugin. You can exclude a category from showing up on homepage, and the posts which you don't want to show up in homepage, you can add those those posts in that category.