Big changes are coming to eBay.

Starting Feb. 20, the online auction site will block sellers from leaving negative feedback about buyers.

It's causing uproar among the eBay community, with many sellers already signing up with rival auction sites.

eBay, the world's biggest online auction site, has a problem.

The number of people using the site has leveled off.

So the company is throwing out one of the bedrocks of its business model - the ability of both buyers and sellers to rate each other.

"The feedback system has been around for more than ten years, and it remains right at the heart of what makes eBay work," said Richard Ambrose, of eBay UK.

"But it needs to evolve a little bit."

eBay will now strip sellers of their ability to criticize buyers, eliminating the tit-for-tat some eBay buyers say sellers use to retaliate against them for giving negative feedback.

"Overall, they're changing the policies because they do realize the customer is king, and if you really want to grow your customer base and you want more visitors to actually buy on eBay, then you're going to have to do something to encourage them to shop from sellers without worrying that they're going to be criticized by the sellers," explained Allyson Stewart-Allen, of International Marketing Partners.

But eBay's sellers are up in arms.

"This means we have no voice, we have no way to defend ourselves," declared Fergus Mumford, an eBay seller.

Mumford works for a company that helps people sell things on eBay.

Selling weird and wonderful items on eBay is the company's business, and it depends on its reputation.

But eBay says sellers shouldn't worry.

"As buyers are more honest about their feedback, good sellers are going to stand out more and more," stated Ambrose.

"We're also going to increase the help we give to sellers when they occasionally encounter a buyer who doesn't pay. And we're going to make it much easier for them to report that and get their money back."

The idea is to improve relations between eBay's millions of buyers and sellers, starting by eliminating the sometimes ugly arguments between them.