The first time, I saw the stats, I was amazed. I could not belive they are so unambiguous. I had been sure the Profiles with custom Profile pictures are more attractive, but I had not expected such a difference.
Take a look at the charts below. They illustrate a comparison between public Profile pages with and without a customized Profile picture. As you can see the Profile pages with customized Profile picture were visited more than three times more often than the Profile pages with system-default, unchanged, anonymous picture. The pie chart shows that 76% of all visits to the public Profile pages were visits to the ones with a customized picture, only 24% of the visits were to the Profiles with a default picture.
The most common way visitors get to the public Profile pages is through the "Full Profile" links. Here, the stats are even more striking. People click the link more than four times more often when it points to a Profile with a customized Profile picture. The pie chart data illustrates 'percentage shares of the market', 82% to 18%.
If you have not changed your Profile picture yet, if you have left the system-default, anonymous picture as the picture of your Profile it's time to change it. Add some personality to your Profile page. Change the picture. Just after that one change, your chances to get a language exchange invitation will increace by, at least, 214%.