After people have settled down in the !fediverse since the larger influx from Twitter, many have gotten their own instances. So if you have subscribed to someone you want updates from - but aren't seeing any - have a look at their profile page and see if they have announced their move. #!

Also, reminder: Everyone who have actually setup an account in the fediverse, put a rel="me" link to your profile next to (preferrably above) your Twitter handle on all the places you have your Twitter handle. And then add '@twitter.com' to the silo handle, to indicate _where_ that username belongs.