There's an old stock market adage: "Sell in May and go away, don't come back till Labor Day." Personally, I don't believe in timing the market, especially on the merits of an anonymous maxim, but today's sell-off certainly didn't do much to disprove the saying. That said, there was some actual news today -- global manufacturing is starting to cool down, U.S. companies are hiring more slowly than anticipated -- that substantiated the drop. By day's end, the Dow Jones Industrial Average (DJINDICES:^DJI) had lost 138 points, or 0.9%, to close at 14,700http://www.bloomberg.com/news/2013-05-01/asian-stocks-fall-as-yen-gains-amid-growth-concerns-oil-drops.html.

Walt Disney (NYSE:DIS) was one of just a handful of blue chips to advance today, adding 0.6%. Although the House of Mouse doesn't report quarterly figures until next Tuesday, the stock was buoyed by good results from several other rival entertainment and broadcasting mainstays. Both CBS and Viacom surprised Wall Street today, and with big media beating expectations, investors grew optimistic for Disney's numbers next week.

Cisco Systems (NASDAQ:CSCO) lost 2.6% today, as news that Arista Networks, a rival computer networking equipment manufacturer, has developed a data switch that can move outputs at 10, 40, and 100 gigabits per second, speeds that are orders of magnitude above products on the market just a year ago. Not only that, but the fastest switches are expected to cost about a tenth of what they usually go for. In other words, Cisco is facing some stiff competition. 

After dropping nearly 2% yesterday, Merck (NYSE:MRK) slid another 2.8% today after reporting disappointing sales, and lowering its outlook for the year -- exactly what investors feared the company would do after its rival Pfizer's underwhelming results yesterday.

Lastly, shares of Verizon Communications (NYSE:VZ) slipped 2.8% after a new merger between T-Mobile and MetroPCS, and tough talk from T-Mobile's CEO John Legere may have scared away Verizon investors. Shareholders could also be getting antsy about what's going to come of the $100 billion bid to buy back 45% of the Verizon Wireless business from Vodafone, as Vodafone reportedly wants closer to $120 billion for its stake.

Fool contributor John Divine has no position in any stocks mentioned. You can follow him on Twitter @divinebizkid and on Motley Fool CAPS @TMFDivine.

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