When a user uploads a video, they can add tags. For example, a new video about DataSift might include this set of tags:
"DataSift, big data, new feature, Linkedin Engagement Insights"
Filter for comments on videos tagged with "Lady Gaga":
youtube.video.tags contains_any "Lady Gaga, ladygaga"
Filter for comments on videos tagged "iPad" or belonging to a category that includes the word "mobile". Not all video sites include tags so you cannot guarantee that they will be present. When you filter against youtube.video.tags, you might choose to include a logical OR command:
youtube.video.tags contains "iPad" or youtube.video.category contains "mobile"
Target service: YouTube