There are exactly 100 stocks. Among them you can find:
teva, ebay, chkp, msft, goog, aapl, amzn
As of Jan 08, there are approximately 3,200 companies listed on the NASDAQ. The NASDAQ-100 is an Index that includes 100 of the largest domestic and international non-financial securities listed on The Nasdaq Stock Market based on market capitalization.
The NASDAQ Composite Index(IXIC) tracks down the performance of all the stocks that trade on the NASDAQ. There are over 3200 companies listed on the NASDAQ- mainly technology companies. So the index is indicative of how investors feel these tech companies are performing/going to perform.