Recently active topics in Twitter tagged with missing tweets

Some messages from people I'm following are not showing up in my timeline. For example, my friend Juverna posted a tweet about four hours ago (the text is "@nullalux: he certainly is!"); I can see it at Juverna's Twitter page (http://twitter.com/juverna), but not in my own timeline.

I do have my timeline set up to show replies to other people, and I can see other @ replies in my timeline--but that one is missing. Other tweets have been missing lately, too.

I get only about 3/4 of the messages from a given friend via SMS text. I get all of them on the twitter website but I always notice that several are missing. That is, the website captures all messages from Sally but I only get some of her messages via SMS text. Why?

I have noticed that I am missing many of my friends' twitters/updates when I view them on my twitter home page. If I go directly to a friend's profile page and, for example, they have 4 twitters, I will only see 2 or 3 of those in my list. Why??

twitterrific keeps getting 404 errors and some of other's tweets are missing

I keep running into instances where tweets from all but one or two contacts suddenly disappear. While I'm following 16 people, my twitter.com/home page was only showing updates from two contacts from last night back to Nov. 12th. I had seen other tweets from other contacts during that time, but then they disappeared.

If we're supposed to be using Twitter to keep track of our contacts, it'd help if all of our contacts showed up reliably.

Are missing tweets on the website a known problem today? Someone I'm following posted a tweet over six hours ago and it still isn't showing up on my website feed, but when I go to their page it still says that I am following them and the tweet is there.

Lately I have noticed that some of the tweets by my friends aren't getting updated on my site. Its like im not even following them but i am. Very annoying.

It appears that I've been recieving @replies via SMS but not the original updates - which really isn't helpful, because all I get are completely context-less commentary from people without a clue what they're replying to! All of my device notifications are on with all of the people involved, I can update myself just fine, I just cannot figure out why I'm not getting the original updates... I mean, the service is pretty much useless if I'm only getting selected messages, especially if it's not the original updates. Help? I'm on a Blackberry on T-Mobile if that helps at all.

Also - no sleep hours set - notification settings are set to send me everything - IM is off, device is on. I can't figure out anything else I could have set wrong!