Twitter Question: Why do some tweets by people I follow not show up?

[Rob]

I have noticed that some of the tweets by people I follow won't show up in my twitter feed. I'll see some of their tweets in my news feed, but when I click on their twitter profile I'll notice they've made other tweets that never showed up in my twitter feed. Why is this?

[enfranr]

Usually any tweets that are directed at someone (eg, they start with @____ ), don't usually show up on someone elses feed unless that person is following them.

For example, if person A is following person B, and person B makes a tweet which is directed (@) at person C, the tweet won't show up on person A's feed unless they are following person C.

That should be the only time when tweets don't show up - however sometimes it can occur for no reason.