safe/risky/? to buy from it.
Both!
With 25 million visitors per month, it is like the entire NYC Metro Area wanting to "make a deal" all at the same time.
The opportunities are wonderful and the risks for scam also exist.
Craigslist is more "unmonitored" than other online auction/sales venues such as Ebay.
Once you receive a reply and make a reply, the activity and security burden is upon you.
Since the "purpose" is usually to buy/sell an item, rent a property, offer or get a job, the need to receive and give personally and financially identifying information is part and parcel of the exchange.
The same rules of safe suffering apply.
Be wary of clicking on attachments.
Be wary of requests for information that go beyond what is necessary for the deal.
If responding to a job posting, the offer should first provide complete company information that you can check out via other methods.
Watch for telltale indicators of grammar and spelling.
Be wary of "mistakes".. such as the buyer sending more money than the stated cost, and then asking you to refund the overage.
There are way more methods to pose a scam, than I could ever possibly address here.
And since the "purpose" of any posting is financial transaction and/or personally identifying information, it is bound to attract a segment of folks whose only purpose is to stage their con.
There are good, even great deals available.
There are risky and too good to be true opportunities as well.
If you are not knowledgeable and capable of securing your own safety/certainty in a transaction… stay away.
I don't do business via Craig'sList.