All of those things can be logged on the server side and most likely are. However, this is nothing that you will or do have access to.

Thanks Jason for your reply. So what you're saying is that Yahoo does oversee the activity on my account, but they will not release any information to me about who is logging into my account, correct?

Yeah, that is what I am saying. Yahoo most likely logs all activity on their servers...pretty much everyone does. How long they keep this information is up to them. As for them giving it to you, you have to look at it from their perspective. Unless you are a paying customer, they really don't know you much better than the person that stole your login information and changed it. I still think you can get your Yahoo! account back, it is just a matter of time and persistence. Read some of the threads here. There are many people that have had their account hijacked, the persistent and smart ones are able to get them back.

Its likely that you will have to provide detailed info to Yahoo as I had to when my account was phished. I eventually wore down on Yahoo and got my account back when they asked me what my new alternate email will be to send the password to because my old alternate email went out of business and they verified this. I did also notice on my account that they do not show your b-day and other accoutn info so the hacker does not see that. It makes it easier to retrace your account to the real account holder so they can send you another password to your alternate email. BTW, did you try retrieving another password using your alternate email?