What kinds of variation suggestions will I get?
Anything to help make the buying process more clear, though it usually looks like 3 main types of notes: size, style, and color. These notes are combined, if applicable (eg. Size: 9, 10, 11.5 | Color: Black/Red)
What is a seller-to-seller note?
These are notes offering help in a way that metrics maybe don't show as explicitly. Some notes might express trends on the Keepa graph, seasonality, or competition expectations in the future (eg. Amazon can't stay in stock, increase the buy box price.)