Rose: That's because IE is not a browser, but a strategical weapon. Its intent is not to give you a good internet experience. If that were the case, MS would have developed it constantly, but they didn't do anything about it when there was no threatening second browser. Its sole purpose is to be the quasi standard and to let people get used to it. It doesn't conform to any standards - if you try to develop valid in means of w3c-standards, IE will kick your a**.

It accepts a mess and renders it. That might sound good - but is actually bad. It's the main reason why more than 90% of the internet is not standards compliant! And it simply ignores a huge stack of standards, especially CSS (just consider their broken Border-Box-Model). That's why it is hard nowadays to develop both correct and successful in the meaning of reaching out to many people. If you want many people to see what you are doing, you have to consider IE. If you consider IE, your design gets broken.

Just consider you wouldn't have tested your site on FF: You would have thought, that using the "alt" tag was actually correct, and would have expected your users to see those titles. You wanted to do everything correct and cared about the user. The user also did nothing wrong. And despite it might look like FF was lowering the user's experience by simply not displaying the (intended) titles, it was acutally IE which made you think you could use alt when you had to use title.

IE is a pain in the a**. Please, everybody: Use Firefox! If you don't like Firefox, use Opera. But NEVER use the Internet Exploder. It really plainly sucks.