A method for selecting content to be presented, the method comprising: Receiving, using a hardware processor, a request for a first video content item from a user device; Determining, using the hardware processor, that the user device is currently in a background playback mode in which audio data of video content items is played back and in which presentation of video data of the video content item is inhibited from being played back; Determining, using the hardware processor, whether the first video content item is suitable for presentation in the background playback mode based on one or more properties of audio data of the first video content item; in response to the determining that the first video content item is not suitable for presentation in the background playback mode based on the one or more properties of the audio data of the first video content item, setting, using the hardware processor, a first background playback mode indicator associated with the first video content item to indicate that the first video content item is not suitable for presentation in the background playback mode; based on the determination that the user device is currently in the background playback mode and the first background playback mode indicator associated with the first video content item indicating that the first video content item is not suitable for presentation in the background playback mode, selecting, using the hardware processor, a second video content item that is associated with a second background playback mode indicator that indicates the second video content item is suitable for presentation in the background playback mode, wherein the second background playback mode indicator associated with the second video content item was set as being suitable for presentation in the background playback mode based on the one or more properties of the audio data of the second video content item; and in response to selecting the second video content item, causing, using the hardware processor, audio data associated with the second video content item to be presented by the user device whilst inhibiting the video data associated with the second video content item from being presented by the user device, such that presentation of at least part of the requested first video content item is skipped and/or replaced with the second video content item instead of the requested first video content item. Receiving, using a hardware processor, a request for a first video content item from a user device; Determining, using the hardware processor, that the user device is currently in a background playback mode in which audio data of video content items is played back and in which presentation of video data of the video content item is inhibited from being played back; Determining, using the hardware processor, whether the first video content item is suitable for presentation in the background playback mode based on one or more properties of audio data of the first video content item; in response to the determining that the first video content item is not suitable for presentation in the background playback mode based on the one or more properties of the audio data of the first video content item, setting, using the hardware processor, a first background playback mode indicator associated with the first video content item to indicate that the first video content item is not suitable for presentation in the background playback mode; based on the determination that the user device is currently in the background playback mode and the first background playback mode indicator associated with the first video content item indicating that the first video content item is not suitable for presentation in the background playback mode, selecting, using the hardware processor, a second video content item that is associated with a second background playback mode indicator that indicates the second video content item is suitable for presentation in the background playback mode, wherein the second background playback mode indicator associated with the second video content item was set as being suitable for presentation in the background playback mode based on the one or more properties of the audio data of the second video content item; and in response to selecting the second video content item, causing, using the hardware processor, audio data associated with the second video content item to be presented by the user device whilst inhibiting the video data associated with the second video content item from being presented by the user device, such that presentation of at least part of the requested first video content item is skipped and/or replaced with the second video content item instead of the requested first video content item.