Alibaba have really come a long way since a few years ago. I was involved in importing from a company who was listed on the site about 4 years ago and it looks like now they've got a few different safety measures in place.

Obviously if you don't do your due diligence it can be risky however theirs a few steps you could take to minimise any risk. A company on Alibaba can opt to be "A&V Checked" which is essentially someone from Alibaba visiting the factory and checking out their business licenses and other documentation. Look out for suppliers who have this on their page. Also, back when I was involved the main payment option was Western Union which is extremely risky. Nowadays Alibaba implemented an Escrow payment which means you don't pay until you receive the goods.

Then there's the whole "Gold Supplier" which is paid membership to the website. Gold Suppliers must be authenticated & verified by a 3rd party which basically eliminates anyone looking to scam you out of a quick buck.

Like any online community there are the scammers & untrustworthy individuals however most are legitimate businesses looking for a new source of customers.