The friendship link on the site would need to go both ways. Request and accept. There is no concept of “Follow”.

In addition, I’d say limit the number of “friends” a person can have. Maybe cap it at 200 (Dunbar's number plus a little extra). This eliminates celebrity, news, and meme accounts. It also eliminates people playing the silly game of seeing who can get the most followers or bragging about follower counts.

These are your actual friends, who also consider you a friend. Even if a celebrity were to join, the site would be useful for sharing with actual friends, not their fans or casual acquaintances.

Facebook started out similarly, but I don’t think it ever had a friend cap. I remember some sorority girls try to get me to make a Facebook account around 2004/5, because they had a contest to see who could get the most friends. I thought this was stupid and said no. Since this happened almost instantly after launch, I think those friend limits are important to make people use it for actual friends and not a popularity contest. Facebook went the opposite way, leaned into it, and created the Follow option. It was all downhill from there.