Hypothetically assuming I had a product targeted at people who were technically capable of developing mashups (or, for that matter, had ever heard the word), I would want to have them use a published API rather than my HTML, because I routinely need to change my HTML. I do not want to have to give everyone 6 weeks of notice every time I do a split test to avoid breaking my core users' sites.
It's not a bug, it's a feature!
Hypothetically assuming I had a product targeted at people who were technically capable of developing mashups (or, for that matter, had ever heard the word), I would want to have them use a published API rather than my HTML, because I routinely need to change my HTML. I do not want to have to give everyone 6 weeks of notice every time I do a split test to avoid breaking my core users' sites.