blue line: oral
green line: vaginal sex
red line: anal sex
Thus, OVA (Oral, Vaginal, Anal).
People can be added to the 'web', from both sexes, as long as two or more current people on the OVAWeb have hooked up with the person, whether it be oral, vaginal, or anally.
Basically, it's a graphical version of 'eskimo brothers'.
And the fun begins...