Until recently it didn't even have a proxy system to communicate with people! That is representative of how little CL cares about making its system better (and it was a real problem). It has never addressed spam, it also has no buyer/seller rating system, which it could have as a feature (yet not a mandatory one). I am not one of the type to meet CL people only at parking lots after getting my buddy with a rifle 50 yards away to spot the whole transaction, but some people are, and CL could attract these people with a rating system of person.
Spam is easily ignored, a lot of CL is people selling something one time (a rating system on CL isn't worth doing, basically). It doesn't need to be any more complicated. People would like it to be something greater, and if they did everything people suggested, guess what it would be? eBay. We already have eBay.
Rules: daylight, busy area with cameras, phone numbers and
if it seems shady don't do it.
Using these simple rules, CL has been a great resource for buying, selling, and trading for me.
I don't go to the ghetto, I don't meet after dark behind buildings, and I hold the cash (cash only of course) if you want to hold the item.
It's not as complicated as people make it out to be, and
so much better than eBay.