Blue-chip stocks have oscillated between positive and negative today as investors and analysts await Wednesday's release of the Federal Reserve's notes from its most recent Federal Open Market Committee meeting. With roughly an hour left in the trading session, the Dow Jones Industrial Average (DJINDICES:^DJI) is off by 22 points, or 0.15%.

In the absence of economic data, today's market moves are likely grounded in the performance of individual stocks. The biggest news to hit the wire was the announcement that Yahoo! (NASDAQ:YHOO) is acquiring the online blogging forum Tumblr for $1.1 billion. In an interview with The Wall Street Journal, Yahoo! CEO Marissa Mayer, formerly a high-ranking official at Google, said the deal will increase the company's user base by 50% and Web traffic by 20%. "You only do an acquisition of this size and scale if you find an exceptional company, and Tumblr is that," Mayer noted on a conference call today.

On the heels of this news, shares of Yahoo! are trading higher by 0.5%. The disconnect between Mayer's rosy predictions and the reaction of the market boils down to skepticism over the deal itself. To be sure, Yahoo! needs all the good news and "synergies" it can get. But whether the acquisition of a "six-year-old company that has no profit and barely any revenue" is the answer, as the Journal points out, remains to be seen.

Moving on to the more traditional blue chips, American Express (NYSE:AXP) is the best-performing stock on the Dow this afternoon, up by 1.5% at the time of writing. As my colleague Dan Dzombak noted earlier, in the absence of economic news, one is left to conclude that American Express' performance today is simply a reflection of the ongoing, albeit slow, recovery in the economy. Because it's both a lender and a payment processor, the company is particularly well-positioned to benefit from any pick-up in consumer spending and underlying credit trends.

Heading lower, alternatively, are shares of Cisco Systems (NASDAQ:CSCO), down by 1.4%. After reporting quarterly earnings last week, Cisco watched its stock soar by nearly 14% due to an impressive performance on both the top and bottom lines. It's obviously giving back a small portion of those gains today, as investors are likely taking profits and reconsidering the company's near-term prospects.