It feels good to know when someone enjoys what I've written.
There's a discussion around the visibility of "Favorites" on micro.blog. Some people want them to be a sort of bookmarking tool only for the person adding the Favorite. Others want them to resemble other social networks, in that they prefer "Favorites" (aka "Likes") to be visible to all users. This benefits the network by encouraging everything to become a popularity contest and is exactly what I don't want.
Opinion: Likes should be visible to only the Like-or and the Like-ee. Liking something is a simple, unobtrusive way to let someone know I appreciate what they wrote. It's also a way to get a little bump when someone likes what I wrote. No one else need be involved.