Amazon.com is shutting down their E-Commerce Web Service 3.0 webservice, as of March 31. ECS3 has been deprecated in favor of Amazon Associates Web Service 4.0. Yeah, there's some marketing speak in there, but basically, they had an older version of their webservice still available, and it's going away now.
How is Tellico affected? I made the switch to what was then called ECS4 in November 2005 and have continued to update the API as additional features have been added. The first released version of Tellico with that access was version 1.1, in February 2006.
Amazon has been sending me emails about Tellico's token still being used with the ECS3 service, so I know there are people out there with versions prior to 1.1 who are using Amazon's search. After March 31, those data sources won't work. Just so you know. (The app will work, you just won't be able to search Amazon.) Upgrade!