Key concepts:
Video search on YouTube from a mobile device
Video search on YouTube from a desktop
Lately the video descriptions started to be given less importance for the user, especially in the mobile version. Here is where they are not even shown in the search anymore, not even while playing it, unless you specifically press the button to show them. On a desktop, barely 2 rows are visible in the search results.
So what should we include in the descriptions?
Emojis that catch attention, especially colourful ones;
Links to connected videos;
Connected keywords (including long tail ones), not included in the title, yet helpful for YouTube to understand what you’re talking about:
Gifts, special offers, if the case.
Think about the persons that may look for content similar to yours and how or what would they search in order to get to that information. Include these words in the description, yet mind that it should have a certain logic for the reader also, not just for the search engine.
The description however should not contain the tags (you put them separately) and tags-hashtags are not very useful either as this platform is not (yet) based that much on them.
Don’t focus nor spend too much time anymore in the descriptions and shift your attention to other tricks we showed before. That will help you position yourself better, get more visibility and boost the number of subscribers.