I fail to see how going to an ad page is a worse offense than going to Drafts as opposed to Inbox. Either way the person in question has to correct the mistake. Expensive in what way? Money, time, embarrassment? I don't see the difference.
At first it's going to be confusion. It's the difference between quickly being able to understand the mistake (because the whole interface is still on the screen, with the pointer maybe in the same position) vs. suddenly being on a completely different site. Keep in mind that this is a missed link, so the user may not immediately know what has been clicked.
After the guy has been using Yahoo Mail for a while and the peril of that ad is well understood, it's just going to become really really annoying, getting sent off-site, every time he hits it. And he will hit it.
Could it be possible they have it there because they consider that you are more likely to see it there and not that you'll accidentally click on it?
Sure. But is that the best choice? That's the question. Like you say, even fully able-bodied people sometimes click the wrong link. It seems like a good idea to take that into consideration when placing what may be the two most trafficked buttons within your interface. I'm not assuming nefarious purposes on Yahoo's part.
I can't say what the optimum vertical height of a button should be for a shaky person. Gmail serves my purposes fairly well without making many design compromises.
At first it's going to be confusion. It's the difference between quickly being able to understand the mistake (because the whole interface is still on the screen, with the pointer maybe in the same position) vs. suddenly being on a completely different site. Keep in mind that this is a missed link, so the user may not immediately know what has been clicked.
After the guy has been using Yahoo Mail for a while and the peril of that ad is well understood, it's just going to become really really annoying, getting sent off-site, every time he hits it. And he will hit it.
Could it be possible they have it there because they consider that you are more likely to see it there and not that you'll accidentally click on it?
Sure. But is that the best choice? That's the question. Like you say, even fully able-bodied people sometimes click the wrong link. It seems like a good idea to take that into consideration when placing what may be the two most trafficked buttons within your interface. I'm not assuming nefarious purposes on Yahoo's part.
I can't say what the optimum vertical height of a button should be for a shaky person. Gmail serves my purposes fairly well without making many design compromises.