Robin Bloor has seen the light:

It took me a whole five minutes to decide to ditch Internet Explorer and switch to Firefox. Why? The learning curve is about 5 minutes – at most. FireFox is simpler to use. Configuring it is easy and would probably be easy for just about any PC user. You are not faced with the typical Microsoft feature-bloat.
Mozilla Firefox has a better layout and a larger web page area. It loads all your Internet Explorer ‘favorites’ when you install it on MS Windows and blocks pop-ups completely (there is an option to allow them on specific sites).
That’s it. Goodbye Internet Explorer, hello Firefox. The clincher was blocking pop-ups. My web surfing experience has now improved 200 percent. I had previously downloaded a plug-in for Internet Explorer that was supposed to stop pop-ups but some got through. Now none get through unless I let them.

And from there he went on to discover the beauty of Thunderbird:

I didn’t feel the need for a better browser, until I found myself using one. Now I even feel grateful. I can also tell the same story about Mozilla Thunderbird. I’ve converted. It is better than Outlook – for my purposes at least. It has all the features that matter, you can convert data (address book and mail) from Outlook in about 1 hour and it stops spam. (Not all of it so far, but most of it.)
With any luck someone will post a comment that draws my attention to some neat feature of Thunderbird that I’ve not yet used, but it doesn’t matter really. I’ve kicked the Outlook habit…
Now, I’ll happily load Firefox and Thunderbird onto Windows, but, if it were available, would I ever load Internet Explorer onto desktop Linux?

(note: emphasis mine)

An excellent question, and one I don’t know if Microsoft can answer. Having your eyes opened by truly excellent software can get you asking things like that…