It is highly recommended you use the MerchantList feed in conjuntion with the Codes and Offers feeds otherwise it is likely that you will not accurately match up the codes / offers to the merchants you have in your own database.

Use the MID's and ICID's to match up data. (Recommended)

The MID's and ICID's are the unique identifiers for the Types.. merchants, codes, offers, these ID's never change and are unique to either the code, offer or merchant globally throughout our API. (Always check against the Type as a code or offer may share the same ICID, but two codes will never share the same ICID and nor will two offers or merchants)

Do NOT use the networks merchant id to match up data. (Not Recommended)

The merchant id in the feeds is the id of the merchant to build the affiliate links, and depending on the network (e.g. Linkshare, Buy.at and Commission Junction) this is not the actual identifier used to identify the merchant itself. Also the merchant id's are only unique to the network and the same ID can be shared on other networks.

Do NOT use the merchant name to match up data. (Not Recommended)

The merchant name is certainly not recommended to match up data because a merchant may re-brand, or the formatting of the merchant name maybe altered for various reasons and so cannot be relied upon as a unique identifier.