Here's some statistics about number of active personal ads from the Dallas / Fort-Worth Craigslist Personals / Casual Encounters section.
m = man
w = woman
t = trans* (either CD, TS, or other trans*)
m4w - 10,000 ads
m4m - 10,000 ads
m4t - 1,916 ads
w4m - 1,868 ads
t4m - 1505 ads
w4w - 1,336 ads
t4t - 105 ads
t4w - 45 ads
w4t - 5 ads
So straight or gay men overwhelming advertise the most. Women, either straight or gay, have at least the same rough order of magnitude of activity, as do trans* looking for men. trans* for trans* - not very active. Women don't seem very interested in trans* with only 5 ads. (Four of them I counted were for "fully functional" trans women, one for a CD.) Trans looking for women was surprisingly inactive to me - and from glancing through the ads, lots of them were CDs.
I don't know that you can conclude a lot from this, but I thought the relative scale of the numbers in each category was interesting. Maybe it says something about Dallas / Ft. Worth?