Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

The Dow Jones Industrial Average (^DJI 0.40%) capped off a strong week today, climbing 42 points, or 0.3%, to close at yet another all-time high of16,221. Meanwhile, the S&P 500 was sitting equally pretty, after a gain of 0.5% today. A stronger-than-expected revision to the third quarter in the Commerce Department's third and final GDP estimate gave stocks a boost as the government said economic growth came in at an annualized rate of 4.1% in last quarter, up from the previous reading of 3.6%. That clip was the fastest growth seen in nearly two years. The robust pace helps explain why the economy added more than 400,000 jobs over the last two months as employment growth often lags other indicators of economic expansion. Businesses need to be confident that demand has risen appreciably before they will hire new workers.

Another factor in play is the market's recent reversal on its view of positive economic news. Whereas before a strong GDP report may have sunk stocks out of fear that it would lead to a stimulus taper, investors seem to have had a "Coming to Jesus" moment with the Fed's very announcement of a taper on Wednesday, and investors now seem ready to believe that positive economic news is, in fact, good for stocks.

Blackberry Limited (BB 1.80%) shares spiked today, finishing up 16%, despite reporting what would be considered an atrocious quarter for nearly any other company. The once-dominant smartphone maker reported a $4.4 billion loss for its previous quarter as revenue tumbled 56%, though the market seemed optimistic enough about the company's prospects under new CEO John Chen to give the stock a boost. The tech company's current turnaround prospects are premised on focusing on software rather than its hardware segment. Smartphone sales fell by nearly half in the quarter to 1.9 million as the once-vaunted Blackberry 10 did not catch fire with consumers. After that recent failure, it seems too hard to put faith in Blackberry pulling off this next comeback.

Walgreen (WBA 0.57%) shares finished solidly in the green today, up 3.7%, after reporting its own quarterly earnings. The drugstore chain said profit increased 68% due to its acquisition of a 45% stake in Alliance Boots, the largest pharmacy chain the U.K. Overall, revenue grew 6% to $18.33 billion, just shy of estimates of $18.35 billion, and same-store sales jumped an impressive 5.4% as pharmacy growth was strong. With Affordable Care Act enrollment currently under way, prescription sales figure to only increase even faster over the coming years. Walgreen's earnings, meanwhile, were in line with expectations at $0.72, and the stock has been a solid performer this year, gaining 50% this year. The company has made a number of smart moves recently, including acquiring stakes in peer drugstore chains and diversifying into groceries to drive sales and traffic, moves that have helped solidify its competitive advantage.