Facebook is set to formally incorporate hashtags into its service as it steps up its battle with Twitter, according to the Wall Street Journal.

Hashtags already feature on Facebook to some extent, entering into common use thanks to their popularity on Twitter to collate Tweets around one subject. However, the WSJ reports that Facebook wants to make their use official and is testing a system that would allows users to click on a hashtag to see posts around similar topics and events.

Instagram, which Facebook acquired last year, already uses hashtags to group photos.

The background to this is the ongoing battle between Facebook and Twitter for advertising: hashtags have proved popular for advertisers both on and off Twitte, as a way of driving conversations about their campaigns and brands.