Assume the SIAI are expert at world-saving and OK at fundraising, and they are short of funds. Also assume that I am poor at both world-saving and fundraising. Then I have Comparative advantage in fundraising.

In other words, I should focus on improving my fundraising ability and then putting it into practice, letting SIAI get on with their world-saving speciality.

Even if there are SIAI fundraising organizations already out there, I'm pretty sure I can apply the comparative advantage thing to them too.

And all this is under the assumption that there is nothing better I could do than raise funds for SIAI.