> I do think that it makes sense, if we have a logo, to have 

the canonical version be a particular vector image, and not 

just, say, a reverse pilcrow typeset any old way. That's not a 

logo, it's just a symbol.

I agree.

I also think that Yuki raised a great point: the logo needs to work (be recognizable) when it's scaled down to favicon size (32x32px). That's a great objective test for a logo. I'll even go out on a limb here and say that I would (most probably) be fine with every logo that passes that test. The test probably weeds out 99% of the logo proposals that I subjectively would feel are amateurish. For an even strong test, scale it down to 16x16px.