To be clear, using the above is turning on an emulated "multitouch", rather than using the trackpad's built-in functionality.
The command 'synclient -m 100' will show the current state of the synaptics trackpad, the "f" column is the no. of fingers detected. For me, with a fresh 10.10 install on a Thinkpad Edge 13, it's only ever 1 (or 0), despite the trackpad hardware supporting multi-touch (xinput list reports a "SynPS/2 Synaptics TouchPad").
Apparently true "multitouch" support is a work in progress (e.g. bug/308191).