NEW YORK (TheStreet) -- Shares of Verizon Communications (VZ) - Get Verizon Communications Inc. Report dropped by nearly 2% Friday, closing at $44.82, in heavy trading of 15.8 million shares. The stock's most recent high was $50.55 on April 28.

The New York-based company's AOL unit announced this week that it would buy Millennial Media (MM) , a mobile advertising company in Baltimore, for $250 million. Millennial's shares closed Friday at $1.74, unchanged for the day. Read TheStreet'sfull report of Thursday's deal.

TechCrunch first broke news of the pending deal in July.

AOL Chief Executive Tim Armstrong discussed the business strategy for the acquisition in an interview with Bloomberg.

BlackBerry Limited'sundefined shares dropped Friday by 2.4%, closing at $7.28, after the Canadian company said it would buy Good Technology, a mobile security company in Sunnyvale, Calif., for $425 million.

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"Like BlackBerry, Good (Technology) has a very strong presence in enterprises and governments around the world and, with this transaction, BlackBerry will enhance its sales and distribution capabilities and further grow its enterprise software revenue stream," Chief Executive John Chen said in a statement, according to MarketWatch.

The two companies have had a rocky relationship in the past, according to the New York Times.Good settled a lawsuit over patents by agreeing to pay an undisclosed amount to BlackBerry, the Timesreported.

Shares of Communications Systems (JCS) - Get Communications Systems, Inc. Report dropped by 6.8% Friday, closing at $8.63. The company's shares declined by 5.2% a week ago, on Aug. 28.

The company, based in Minnetonka, Minn., manufactures and sells connecting and wiring devices, including copper and fiber-connecting systems. There was no news or apparent reason for the company's stock decline Friday.

Communications Systems recently reported financial results that included total revenue of $28 million for the three months ended June 30, compared with revenue of $19.5 million for the quarter that ended March 31, 2015. The company pared its quarterly loss to $1 million, compared with a loss of $4.1 million for the prior quarter.

Shares of Communications Systems were trading at $12.08 on March 13, their most recent high.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.