As we've been using Twitter more and more to communicate with clients and friends, most of the time I find myself doing this on my iPhone. The problem I've been running into is that the twitter apps like hootsuite and tweetdeck don't alert me if I'm not using my phone when someone has replied to my latest tweet like a traditional SMS text message would. This can be difficult to try and carry on a quick conversation when my iphone goes to sleep and then I need to turn it back on to see if someone has responded.