Texts and iMessages on the iPhone?

How come sometimes when you text someone from one iPhone to another, it automatically turns blue and becomes an iMessage, but other times it remains green and just stays a text?

IMessage is for people with iPhones, iPod Touches and iPads only. So if you sent a text to someone else with an iPhone it would automatically be iMessage. If you sent a text to someone who doesn't have an iPhone, it counts as a text.

When you're both connected to the internet it becomes an imessage. When you're not, its just an ordinary text.

I donkey know

  • Why is my Iphone not sending as Imessages and receiving iMessages from one person? I'm texting my wife and we both have iPhone's and she is getting the messages as an iMessage but the ones I'm sending her on my end show up at green. Sometime it will go as blue, get the little red exclamation point then send as regular SMS. I'm texting someone else too and she has an iPhone, and she is getting mine as regular iMessages and mine are sending as regular iMessages. Why aren't they sending to me wife as iMessages?
  • Why does my iPhone sometimes send texts to other iPhones as iMessages then regular texts to iPhones? Like when I send a text to my friend that has an iphone, it usually sends as an iMessage then it will randomly send as just a regular text and it will be green and not blue.
  • Why do my imessages always send as texts? It's not for everyone, just one person. Every time I try to send a text to that person, it's blue for a little bit, then later turns green, sent as a text. And I text other people all the time that have iphones and those messages are always blue. Why does this happen? I doubt their phone is always off or anything like that.
  • Why are my iMessages showing up as texts for certain iPhone users? Okay, so I have an iPhone 4S and earlier today, I tried to text one of my friends earlier who has an iPhone 4S and iMessage wasn't registering when I entered their number, and the texts would only send as text messages. I can send iMessages to all of my other friends who have iPhones without any problems. This friend is the only person it's not working for. I'm not sure what the problem is.