More than 60 percent of Twitter users have stopped using the micro-blogging service a month after joining, according to Nielsen Online research released recently.

‘Twitter has enjoyed a nice ride over the last few months, but it will not be able to sustain its meteoric rise without establishing a higher level of user loyalty,’ said David Martin, Nielsen Online’s vice president for primary research. More than 60 percent of Twitter users fail to return the following month – Twitter’s audience retention rate, or the percentage of a given month’s users who come back the following month, is currently about 40 percent.

Martin said that when Facebook and MySpace were emerging networks like Twitter their retention rates were twice as high and they now have retention rates of nearly 70 percent.