Method for operating a first end user device for transmitting message data from the first end user device to at least one further end user device by means of one or multiple transmission paths, at least comprising the steps: Displaying a user interface by means of a display unit of the first end user device , wherein the user interface comprises a section for defining information by the user which has to be sent as message data , wherein the message data comprises at least some data different from data representing text information, in particular data representing picture information or sound information; Detecting which one of the multiple transmission paths is available, wherein a main transmission path is selected in case it is available or in case a data transmission speed is higher than a predefined threshold, wherein an auxiliary transmission path is selected in case the main transmission path is not available or in case a data transmission speed is lower than a predefined threshold, in response to a detection of a user command sending the message data via the selected transmission path, wherein the selected transmission path is selected from the main transmission path or the auxiliary transmission path, wherein the message data is automatically modified prior to sending in case the auxiliary transmission path is selected, wherein the message data is modified in such a manner to include predefined link message data representing information different from the defined information of the message data which is transmitted via the auxiliary transmission path, wherein the predefined link message data comprises the addition of routing data for requesting data transmission of the remaining message data to the further end user device at a later time, wherein the main transmission path is set up by an internet connection, in particular an instant messenger means, and wherein the end-user devices , are having internet and GSM/CDMA based connectivity capabilities, wherein the auxiliary transmission path is set up by SMS or MMS. Displaying a user interface by means of a display unit of the first end user device , wherein the user interface comprises a section for defining information by the user which has to be sent as message data , wherein the message data comprises at least some data different from data representing text information, in particular data representing picture information or sound information; Detecting which one of the multiple transmission paths is available, wherein a main transmission path is selected in case it is available or in case a data transmission speed is higher than a predefined threshold, wherein an auxiliary transmission path is selected in case the main transmission path is not available or in case a data transmission speed is lower than a predefined threshold, in response to a detection of a user command sending the message data via the selected transmission path, wherein the selected transmission path is selected from the main transmission path or the auxiliary transmission path, wherein the message data is automatically modified prior to sending in case the auxiliary transmission path is selected, wherein the message data is modified in such a manner to include predefined link message data representing information different from the defined information of the message data which is transmitted via the auxiliary transmission path, wherein the predefined link message data comprises the addition of routing data for requesting data transmission of the remaining message data to the further end user device at a later time, wherein the main transmission path is set up by an internet connection, in particular an instant messenger means, and wherein the end-user devices , are having internet and GSM/CDMA based connectivity capabilities, wherein the auxiliary transmission path is set up by SMS or MMS. <EOS>