Meta has started rolling out a new update that means that link clicks and landing page views campaigns will now automatically include audience expansion, with the advertiser being unable to turn this off.
Audience expansion is where your campaign will occasionally go beyond your specified detailed targeting (interests, age, gender etc.) if it believes it will drive better performance in doing so. This can be a fantastic tool when driving purchases, but falls down when looking at top of funnel campaigns.
If your ad is going after those most likely to click, outside of your set audience parameters, there could potentially be a lot of poor quality traffic coming through your ads. It might drive low cost clicks but they might be less likely to take an action after a click, may not fit your audience profile (think B2B businesses with specific industries) etc. The algorithm will go after the lowest cost action.
This is quite a big change and will need to be factored into discussions around paid social as a tool for driving high quality website traffic.
