You can add tags to your campaigns. This helps you to find campaigns with certain themes.
There are two ways to add tags - while creating a new campaign and from the detailed view of a sent campaign.
Adding tags while creating a campaign
On the last (4th) step of creating a campaign you can enter a tag or several tags. Just type the tag in the "Tags" box on the bottom right of the page, as shown on the picture below.
Adding tags to a sent campaign
If you have already launched the campaign or you want to add a tag to an older campaign, go to the campaigns list and click on the campaign you want to add the tag to. The detailed view opens. You can add the tag(s) to the campaign in the bottom right of the screen, just type the tag in the "Tags" box.
To find the campaigns by tags, just use the usual page searching option. Go to the "Campaigns" menu and press Ctrl + F. A little search box appears. Write the name of the tag in the search box, then the words you were searching for will turn colorful on the page and you can see, which campaigns contain that tag.