I use them a lot on allaboutberlin.com, because some readers are familiar with certain things and others are not. This lets me serve both audiences while keeping the guides short and straightforward.
I very rarely use footnotes except for citations, unless it's a precision that would be useless to all but the most erudite readers.
I very rarely use footnotes except for citations, unless it's a precision that would be useless to all but the most erudite readers.