Fair question, Harks... I think it comes down to the fact that transacting business is based on trust. I trust that companies with physical stores (other than the temporary Halloween and Christmas ones) will be there in the future, should I have a problem. I trust that sites like Tigerdirect and Sam's Club are safe on the web because they have physical stores, and the web is an extension of that. I trust sites like Amazon and iTunes because they've built up a reputation.
eBay itself has a reputation, and that makes it trustworthy. I suspect Kijijijjijijijij (or whatever it is

) is the same, and like eBay, allows buyers and sellers to be ranked. That allows you to build on the trust from other buyers and sellers.
And frankly, Nigeria has built a reputation as well... of untrustworthiness! That link I had there included some posts from someone in Nigeria, trying to do legit business... unfortunately, his countrymen's actions make it nigh on impossible for anyone to trust him unless they know him personally on some level.
The way I've usually done it, you win an auction, pay for it, and the seller ships. Some do indicate that they're going to withhold the shipment until payment clears. Others just indicate that they won't ship out of their country, or not into specific countries.
So... protection for the buyer? It's there with eBay and others in the feedback mechanisms, along with their dispute resolution approaches. Sadly, anyone from Nigeria is on the low, low end of trust in this area.