Can you give the site's url to see what's going on?

Let me try to find an example again... I'll look in the morning and report back. Too tired now, it's after 1am and I've been working on "honey do's" most of the day, just now catching up with on-line stuff.

Well, actually I found one already...

Just check out E-bay. www.ebay.com

Shows up as IE8 compatible (ie. no broken page option by the refresh button)... Yet on it's logo it displays the "Alt text".

When I went to the Ebay link it loaded in Standards mode and no alt text was visible. I had to hit the broken page button to switch it to compatibility mode and then the alt text showed up.

When you install IE8 you are given the option to opt out of a "feature" that will make IE8 switch to compatibility mode on sites where enough IE8 users have decided there are pages where compatibility mode looks better. Sounds like you may not have opted out of that when installing, so your browser is being switched whether you like it or not.

Check your menu Tools > Compatibility View Settings

Are their sites listed in there. Mine is empty and I don't have "Include updated website lists from Microsoft" checked.

Nope, I have to manually select "compatibility mode" by clicking on the "broken page" icon WHEN it shows up next to refresh.

I checked my list, and have a few sites there (including CC), but no, e-bay is not one of them. I haven't gone through my history yet this morning to find the other sites.

From what I understand through readings, even if IE is going to "compatibility mode" on its own it SHOULD be displaying the "broken page" HIGHLIGHTED BLUE, as it does when you manually select that mode.

Well, simply put, if the page is being displayed in standards mode, which compatibility mode is not, then alt text won't be visible on hover because that's what the standards call for. Any page where alt text is visible either isn't coded to standards or IE8 has been switched out of standards mode.

That may well be. What I can't seem to find any rhyme or reason to is how the browser will choose to show two different sites in Standards mode, but one will show the compatibility button and the other won't. (EDIT: Apparently it depends on whether the page is on the web or local, and if it has an "X-UA-Compatible" meta tag/server header.)

At any rate, an easy way to insure that a site will be displayed in Standards mode with IE 8 and above is to add this to the head of the page: