http://slashdot.org/comments.pl?sid=183244&cid=15137300

Actually, it didn't come from NCSA Mosaic. It came from Spyglass Mosaic - a completely different browser[1]. As for being "legally stolen" well... that's about right, but how they did it was interesting. Rather than buying the code from Spyglass, they licensed it and promised to give Spyglass a percentage of all sales of Internet Explorer. Then they gave Internet Explorer away for free. Spyglass got screwed, but couldn't complain because Microsoft was complying with the letter of the license. (Spyglass did get a quartlerly fee, but that was a drop in the bucket.)

[1] http://en.wikipedia.org/wiki/Internet_Explorer [wikipedia.org]