We saw tech weak with the "safety stocks" leading the way once again this week. When the market sells off, you see a 'flight to safety' in the less volatile names like utilities & industrials. When a leader like AAPL is the weakest stock around on no out-of-the-ordinary news announcements, that is a huge clue to me that the market is shaky.
Often times, you can get more information out of an overall market by looking at the top 10-15 leaders rather than judge things by a massive indices like the S&P 500.
That being said, Mega Caps, financials & energy all held up really well and were first to go green on most down days.