Marketo caches values for faster searching in fields. This is great, and certainly speeds up the database. However since we're technically not natively synced with any CRM, we don't get the official field values in our drop down boxes. So for my industry for example, I have every crappy version that anyone has ever typed in this field. From 0005763 to FinServ to Financial Services / Insurance. It would be really great if I could purge the cached values so that only the proper values show up.
This is one of the most requested features from my users, they find it really confusing to look at the drop down and chose Financial Services/ Insurance vs Financial Services / Insurance vs Financial Services/Insurance.
I believe if you have SFDC natively synced you won't have this problem at all, because Marketo reads the values from SFDC, but without a native integration I have every value that has ever been inputted into that field.