Some people use social media to keep up with people they know in real life. Except for a few outliers, I’d say that was the primary use case before viral games like farmville encouraged the behaviour of friending as many people as you could.

People’s blogs often have RSS.

Interesting. Are there any Activity Stream Readers?

There are some other federated social sites besides lemmy that something like this could be added to, but they’re not as big, afaik.