I hate reading that. Especially if the page was optimized for Internet Explorer which I don't browse with (although I do use it to set up my web pages). It makes me think "I wonder if I'm seeing this page in a crappy light compared to how they want me to view it"...but I didn't always think that way.
I used to think : "ho-hum, some geeky person uses Netscape or whatever" when I was still using IE. Of course things have changed. Of course I am aware of the world of choice that I knew existed before but was a bit too cowardly to delve into. Some people are prepared to put up with a lousy browsing experience for a long time rather than be forced to try something different.
There was a time when I DID NOT KNOW THE DIFFERENCE BETWEEN a web browser and an internet service provider! I also didn't understand that all software is optional- what came 'bundled' on my first laptop was the result of a deal between Microsoft and Compaq Computers. (I DID know that the Macintosh computers were different from most other computers but that didn't really interest me- crazy Mac addicts! lol )
The point is, I , like many other people, used Internet Explorer to browse the web and learned basic html coding using it alongside Notepad to edit my pages. I started to pay attention when I noticed some sites looking strange and having the little 'optimized' messages on them, and began reading about how html coding was becoming standardized and even replaced with new styles of coding but that the browsers (Internet Explorer being only ONE of them) had propitiatory codes you could use which in effect would mess up all the good intentions of standardizing html. At least thats how I saw it.
(On a somewhat relevant note I learned what the terms propitiatory, default, bundled, and end user license agreement meant during that time and feel obligated to express my STRONG opinion that Microsoft should never have been allowed to include their browser with the operating system it supplies. I don't know why it still does but hopefully other browsers are now better able to compete from the onset)
My final words on this subject are this: "This page is optimized for..." is just another way of saying "I'm too lazy to see if my page looks good outside of the program I'm currently using". Yes, I said LAZY. I don't care which browser people want to use- there shouldn't be a disclaimer on your pages telling the world you would prefer them to be using your choice of software. (This is important as well for people who hire web designers to make their web pages.)
I downloaded Mozilla a couple of years ago, then Firefox, and finally this year Opera. I don't use Mozilla anymore because Firefox is quite similar and a lot faster, and I got Opera because it's more customizable for people with bad eyesight. (Minimum font size option applies to ALL pages and tabs). I look at all my new web content in at least 2 browsers to make sure that it all looks legible and so does my husband who has a fussier site that is more professionally oriented.