When you create a post in WordPress you can assign it categories and you can assign tags. What is the difference?
Categories allow for a broad grouping of post topics. For example if you blog about traveling, you might have a category for posts dealing with a specific country like “Italy”, “Tanzania” or “India”.
Tags are generally used to describe your post in more detail. So your blog entries might use tags like “Couscous” , “food”, “Mint tea”, “lamb” if you blog about food you have eaten in Morocco.
Categories can be arranged in a hierarchy, Tags cannot.
If in your travel blog you have a category named ”Europe”, you might have sub-categories named “Italy”, “Germany” and “France”. Tags, however, exist in their own right and have no set relationship to anything else. You can re-use your tags however and in that way group otherwise unrelated posts together, for example if they mention “Mint tea”.
Categories as menu items
Another great use for categories is that you can put them in a drop-down menu. So you could have a link to your travel posts about Europe in the main navigation and then have drop-down links to Italy, France and Germany.
Is there a limit to the number of tags I can have?
No limits, go crazy!