The Mekko chart below shows monthly visits to major social networking sites by gender. The width of each column is proportional to total number of monthly visitors. The x-axis is visible and labelled too. Within each column the segment height is proportional to percent of female/male users.
The largest social networking sites, YouTube and Facebook, have roughly and equal number of male and female users each. Soundcloud has the highest proportion of male users (61%) and Tumblr has the highest proportion of female users (72%).
This Mekko or Marimeko chart was built on Mac with OS X using Aploris and PowerPoint for Mac.