Okay Verizon, you finally convinced me to get a smartphone so I can text, etc. Now I find that only other Iphone users can get my text messages. This is very annoying. My family members are Verizon and other carriers, Iphone and Droid users but I find that only some can receive or send me messages. What is up with this?
That is because you are not sending texts, but iMessages. iMessage is an Apple proprietary messaging system which DOES NOT utilize SMS, but instead chooses to send messages counted against your data allowance. iMessage is ALSO only available to Apple phones.
Go into your settings > messages > make sure that the box is checked to send as SMS if iMessage is not available is checked. This way, when your iPhone cannot send an iMessage to a contact, it will send an SMS.
Personally, I think you should completely disable iMessage and only send SMS messages. With Verizon, most plans now include unlimited texting and an allowance for data. If you use iMessage, these messages will count against your data allowance where these same messages sent as SMS would not since you most likely have unlimited texting on your account.