TXTMob was used as a model service during the development of twitter.
Step-by-step explanation:
The service called TXTmob provided by twitter helps in sending messages to some person or form unknown persons. It helps the users for sharing the text messages of handheld phone to be shared with other persons. For communicating with other persons or groups using this service needs the user to sign in. This was used in the twitter development.
Using this service the messages can be sent to any groups in which all the messages will be sent to the all the members of that particular group. A txtmob member is eligible in joining to a public group. When the txtmob member attempts to join this private group then it will be like pending. It is the system administrator who has the authority to check and approve the membership of the individual.