An esteemed colleague at Yahoo! Search is retiring this year, at the age of 65. He started working in the tech business in the early 70’s, and over the last 30-odd years has worked in different sub-industries in several different well-known companies. Yet during that entire time, he has never once quit, or been fired, or been laid off. How can this be?
Tech career puzzle
Tim Converse 
Yahoo bought X, which had bought Y, which had bought …
That was my first guess, but now I’ll instead say… He’s learned to make very good use of sabbaticals?
Yes, the answer is acquisition. I think the companies involved were DEC, Compaq, Altavista, Overture, Yahoo! (though I may have missed one or two).