1. A non-transitory computer-readable medium embodying a program executable in a computing device, comprising: code that stores, in a memory, a user catalog of items; code that identifies an unmapped attribute of an item included in the user catalog of items in response to determining whether a first format of the unmapped attribute is recognizable by a system platform; code that extracts a value of the unmapped attribute encoded in the first format according to historical data of known attribute-value pairs; code that generates a plurality of recommended metadata maps, wherein one of the plurality of recommended metadata maps translates the first format into a second format; code that applies the one of the plurality of recommended metadata maps to encode the value in the second format; code that generates a system catalog of items, wherein the system catalog of items comprises the item and the value encoded in the second format; and code that maintains a plurality of metadata maps developed, at least in part, by a plurality of users.