Take one minute of video. Look at the file size. Now how many of these 1 minute files can you fit onto an 8GB card in your particular format and camera/device.
SMS stands for Short Message Service, which is the formal name for text messaging. It's a way to send short, text-only messages from one phone to another. These messages are usually sent over a cellular data network. That's not always true, though, as in the case of iMessage below.
Text Message. A text message, which is also known as SMS, is the text messaging component built in to any modern phone. It allows the exchange of text messages between mobile devices or fixed devices that have the ability through a standard set of protocols. The history of SMS lies in memo pagers and then it was standardized as a part of the Global System for Mobile Communication; what we know as GSM; in 1985.