The efficient market hypothesis is applied not only to stocks, but to a wide range of, most especially financial, assets.
The hypothesis only implies that the market values assets correctly in the sense that the current market price of any asset is the best indicator of the future value of the asset.
It is not true that the efficient market hypothesis requires observable information to arrive randomly. However, it is true that new information must arrive randomly. If it did not, market participants could predict the coming information and so would in effect already already know it. As a result, it could not be new.
A further implication of the efficient market hypothesis is that changes in asset prices can can only reflect new information. This is the only information rational investors act on (arbitrageurs eliminate the effect of irrational actions). Investors' decisions to buy or sell an asset on receiving new information incorporates the news into the asset's price. Thus the news becomes old.
Another implication of the efficient market hypothesis is that no one (not even Warren Buffett) can get rich trading on the stock market, except by gaining access to new information and being able to act on it ahead of the market, that is while it is still new. Fortunately for all those day traders and other investors out there, the efficient market hypothesis is empirically a failure. Unfortunately, the empirical evidence also suggests most traders and especially small ones still lose money.