I believe you can still solicit for prostitution on Craigslist. They may have removed the "adult services" section, but I'm told the personals still are filled with vaugely disguised ads for "escorts", etc. Guns, however are a big no-no.
That's correct. They don't allow firearms. I see guys list "hunting equipment for sale" and when you click on their ad, they give a number for you to call for information.
Or sometimes when you click the ad they give the description of the weapon, but then it gets pulled.
Oh, and IIRC, they forbid advertising firearms, not because they're leftist trash, but because they got pulled into a lawsuit where somebody got shot with a firearm purchased off craigslist.
They are headquartered in San Fransicko, after all.