As you can see from the article, facing in toward the caregiver's body is really the way that babies should be worn most of the time. Some people recommend never having baby facing out, but I know a lot of parents want to to be able to do that as I get a lot of questions about that. I usually recommend that if caregivers want to have their baby facing out, they need to take some things into consideration.
First, as the article mentioned, it is important to make sure the baby's legs are in an ergonomic position as can be achieved with most properly designed baby carriers and all the ones I sell. They should not be danging from their crotch, but should be in a seating position.
Second, as mentioned, babies can't take cues from their caregiver's faces when in social situations, but also, something the article didn't mention, is that babies have no place to turn away from overwhelming stimuli when they're facing out. So the caregiver needs to be aware of the mood of the baby and make sure to turn them back around to face their body if baby gets too overwhelmed by the social situation.
Also, the article doesn't mention that when baby is facing out, the baby is not in line with the babywearer's center of gravity, so they will find it uncomfortable for long periods of time as baby is just hanging off the front of them. Another thing to consider, especially with an older baby is that now you have two arms and two legs that can reach a lot of stuff when directly in front of you, so beware! Hope that clears up some of the questions. So if you want to wear your baby facing out, after they can hold up their head, go ahead, but do so sparingly and make sure you take these things into consideration. Happy Babywearing!