Concatenated messages can only fit 153 characters instead of 160. For example, a 177 character message is sent as 2 messages. The first is sent with 153 characters and the second with 24 characters.[14] The process of SMS concatenation can happen up to 4 times for most bulk SMS providers, which allows senders a maximum 612 character message per campaign.
Sample size indicates the size of the group of people who are going to receive your message. The size of this group and the amount of conversions you’re getting determines the significance of your test. Significance refers to whether we can rely on the made changes to have generated these results, or whether we can’t rely on the changes, but see that the results were simply due to chance. What this really means is that we want to be able to say: we can be 95% sure that the changes we made will improve our conversion rate. 
To learn how your message can be improved, it’s important to analyse the results. Which parts of your message are not performing as well as expected? Is the open rate lower than expected? Or are people opening your message, but not taking any further action based on the contents of the message? Your analysis will tell you which parts of your message can do better and will help you to formulate your goal.  
Due to the demands for more user controlled media, mobile messaging infrastructure providers have responded by developing architectures that offer applications to operators with more freedom for the users, as opposed to the network-controlled media. Along with these advances to user-controlled Mobile Messaging 2.0, blog events throughout the world have been implemented in order to launch popularity in the latest advances in mobile technology. In June 2007, Airwide Solutions became the official sponsor for the Mobile Messaging 2.0 blog that provides the opinions of many through the discussion of mobility with freedom.[39]
You will have a greater chance of gaining access to their mobile number by following these guidelines. You can collect their numbers using a sign-up sheet at your register, asking them when talking on the phone, allowing them to submit a form on your website, or by giving them a number that they can text to subscribe to your SMS messages. Whatever you do, keep a copy of their permission to market to them via SMS, if you run into problems you will be glad you did.