eBay published the following post on its announcement board on Friday:
Due to Mardi Gras festivities in Louisiana, Alabama, and Mississippi, packages may be delayed between February 24 and February 28.
If you are involved in an eBay transaction with a buyer or seller in this region, we encourage you to be patient in this matter, both throughout the transaction and when providing feedback after your item arrives.
Rest assured that sellers need not worry about their eBay seller performance due to shipping delays caused by Mardi Gras events. We will continue to monitor the situation and include any sellers who may be affected.
Note: presumably eBay got its information about delays from FedEx, which issued an alert on its website; you can download a spreadsheet of affected zip codes.
Source: eBay Announcement Board Post