eBay.com has joined eBay UK in limiting sellers from manually changing the duration of their listings. Two hours after the start time of a listing, sellers will lose the ability to change the duration of the listing using the Sell Your Item form, Turbo Lister, and any third-party tools that use eBay's API.
The announcement read, "These auction extensions disrupt normal bidding patterns, creating a poor buyer experience. Some sellers were also using this ability to gain an advantage for their listings in terms of exposure on the site. In the next few days, the option to extend your listing duration in our listing tools will be modified to be in compliance with this policy change."
The issue of extending auctions came up in a major brouhaha in the summer of 2005, when it was revealed that a developer called Ethical Technologies had been marketing a tool to members of the Professional eBay Sellers Alliance (PESA) that automatically revised listings for sellers. At the time, eBay waffled on whether the practice was allowed. When Ethical ceased operations, other developers created their own auction extenders to fill the demand from sellers.
In January of 2007, eBay told top sellers at its Ecommerce Forum meeting that it had changed its "Circumventing Fees" policy to prohibit the extension of auction durations, both manually and through the use of automatic tools.
http://www2.ebay.com/aw/core/200706111007572.html