Use this field to compare two or more bikes. It is like a search function, except it takes multiple search terms. Eg: "Salsa, Surly Rim"
Each search term must match a string in the title of the bike. Each search term can also match more than one bike. Eg; "Surly,Kona" will match multiple Surly bikes.
You can have any number of search terms. Eg: "Cote,Diverge,Sutra" A single search term just does one match.
Which columns appear on your comparison report is controlled by the "Format" field.
From the document: Form Help for Bike Lister