In February, eMarketer forecasted there would be nearly 158 million social network users in the US this year.
More than half of those users are women, and eMarketer expects this trend to continue throughout the forecast period, though the percentages will not be far off from 50-50.
On Facebook in particular, though, the skew toward women is significantly greater: Nearly 55% of Facebook users this year will be women, down from 57% in 2010 and expected to fall further to 53.2% by 2014.
Read more details on this study at emarketer.