SAN FRANCISCO -- A weeklong boycott against eBay's ( EBAY) revised fee structure ends Monday. But some sellers on the auction site still may be holding a grudge, and that could have a lasting effect on the company.

Sellers initiated the boycott in retaliation against eBay's new fees, which took effect Feb. 20. Late last month, eBay announced that it would charge a smaller fee for sellers to list their items for auction. In turn, sellers would have to pay eBay a higher commission if they made a sale.

eBay touted the change as a benefit to sellers, but not all of them are happy. Some even claim they are paying more in fees now than they had before.

Spokesman Jose Mallabo says the company has felt no impact from the boycott so far. Those participating in the boycott are passionate sellers, he says, but they represent only a small fraction of eBay sellers around the globe. No estimates are available on the number of sellers backing the boycott.

According to David Steiner, president of AuctionBytes, an independent trade publication for online merchants, eBay's listings totaled just over 12 million before the fee change. But then the company offered a listings promotion that helped drive up the number to just under 16 million on Feb. 13. Now that the promotion has expired, listings have fallen below 12 million.

Steiner says the drop can be attributed to any number of factors that might have nothing to do with the boycott. And analysts agree that the effects of the fee changes beyond the boycott have yet to play out.

"My suspicion is that the full impact won't start to be obvious until mid-April," says Derek Brown, an analyst for Cantor Fitzgerald, which makes a market in eBay. "You need to have enough time for sellers to have the changes in front of them, run through a cycle of their listings, and see what the final tallies are to understand what they'll do in the next cycle."

eBay introduced the new fees to boost growth at its sagging auction business, which accounts for 70% of the company's revenue. Its marketplaces division in particular has slowed, with revenue growth falling to 21% in the fourth quarter from 26% during the prior quarter.

eBay's shares have slipped 33% from their 52-week high.

"They're doing what they have to do," says Tim Boyd, an analyst for American Technology Research. "Their core business was getting sluggish. This was two years overdue."

Steiner says those who stand to benefit from the fee change include commodity sellers who tend to have low sell-through rates and end up listing their items multiple times. Those who might lose out are people with high sell-through rates and high final prices on items like antiques and collectibles.

Steiner notes that sellers have boycotted eBay in the past because of fee hikes or policy changes. But this may be the last straw for some of them.

"There's a cumulative effect that erodes eBay's image," Steiner says.

During the last big boycott in 2005, sellers had little choice but to crawl back to eBay. Now, however, the marketplace is much broader, and sellers can push their wares on sites like Amazon ( AMZN) or Google ( GOOG).

"There weren't a lot of second- or third-tier platforms but Amazon has now opened up and they've cherry-picked top sellers from eBay," Steiner says.

Still, that's not to say that sellers will leave eBay en masse just because they can. Boyd says the site continues to offer more opportunity for small players than its competitors.

"eBay is still the best place for sellers who have not achieved scale (required) for Amazon or Google," he says.

Beyond the fee change, eBay is also imposing a new rating system, which will influence the order in which sellers show up in searches on the site and that too could affect eBay's total listings.

A few months ago, eBay began allowing buyers to anonymously rank sellers based on their level of communication, shipping times, shipping and handling charges and the accuracy of their auctioned items' descriptions.

Next month, the company will use those rankings to sort which sellers should appear first in the site's search results. High-ranking sellers will rise to the top while low-ranking sellers will fall to the bottom.

But Brown points out that high-ranking sellers aren't necessarily eBay's biggest sellers, so listings have a potential to fall.

"One of our concerns around the stock right now is the tremendous amount of uncertainty," he says.

Boyd agrees that there is still a lot of unknowns about eBay right now. But at the same time, the company had no choice but to make a move, given the rising competition surrounding it.