WordPress allows you to assign keywords, or tags, to your posts. Tags enable you to apply more keywords to your post rather than bloating your list of Categories. But you should not use a heavy hand with tags, as this can become too cumbersome for your users to search through your tags. And especially if you are allowing Google and other search engines to index your tags.
How Many Tags do You Have?
Bad Tag Names
Many people lose track of what tags they’ve already created and just go ahead and create new ones for every post. If you have a post about interior paint colors and you already have a tag called Color, you don’t need to create a new one called Colors because some of your posts will be found in one instance and some in the other. It becomes sloppy!
Some years ago people started “auto blogging” whereby they used a plugin that would scrape (steal!) RSS feeds from other websites to create posts on their own website. Those folk’s website ranking and traffic took a nosedive – after an initial increase from this practice – when Google caught on to this practice and cracked down on them. This plugin not only pulled in those articles but hundreds or thousands of tags in some cases.
So if you ended up deleting posts either because they were bringing your ranking down, or for some other reason (and the associated tag is not used for any other post), then that tag will have been indexed and now return a 404 page error when someone searches for that tag name.
You have to manually delete unused or repetitive tags. Deleting a few tags is easy, but I’ve seen some websites that have hundreds of tags!
Delete a Few Unused Tags
To see how many unused tags you may have, go to your WordPress admin panel. Under Posts, select Tags. In the section on the right where it lists columns of Name, Description, Slug, Posts, click on Posts to sort by that column. Clicking once should sort that column by ascending order (smallest to largest). If you have tags that have no posts associated with them, they will show at the top of the column:
Sort Tags by number of Posts
If you just have a dozen or fewer unused tags, simply click the checkmark box to the left of the tag name, then click the Bulk Action button at the top and select Delete.
Mass Amount of Tags
If you have a huge number of tags to delete you can use a free plugin called Mass Delete Unused Tags. Once you install this plugin and activate it, you will find the settings under Plugins (normally plugins show under Settings). Open this and select Yes, Delete unused tags and it will do the job!
If you’ve been blogging for a while, you may have created too many tags for similar topics, and you want to merge them all together. You don’t want to just delete these similar tags, but to merge them, thereby giving all posts using all versions the same tag. A great plugin for this is another FREE one! Term Management Tools. Install this plugin and then go to Tags. Locate the similar tags and select them with the checkbox. Click the Bulk Actions button above and you have the options to Merge the tags to one Tag name or even change those tags to a category, but I’ll leave that for another day. Click on Merge and then type in the single Tag name you want to use for all those posts. This can be an entirely new Tag or one of the ones in use.
In my example I decided all posts should have the tag Car and the other tags should be deleted. I clicked Apply and now all three posts that previously had synonyms or plural form for Car will now uniformly use one Tag: Car.
Merging Similar Tags
Be sure, as with any plugin, to run a backup of your site before installing it, then once it is installed and activated go look at the front-end of your site to make sure everything is displaying okay.