A like gate is a technique used on Facebook by which a brand forces or incentivizes non-fan visitors to like its page to access a content or application on an other tab.
Like gating is mainly used for giving access to contests, giveaways, coupons, videos, polls and various contents.
A like gate is an effective but artificial method to boost fan recruitment. The downside is to have many fans who lacked real interest in the brand.
Facebook has early forbidden the like gating of the main or whole Facebook page and it was only possible to like gate a Facebook tab. Since 2014, Facebook has banned the use of most like gates.
Some examples of like gates :