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.

Today was Janet Yellen's coming out party. The presumed future head of the Federal Reserve spoke before the Senate banking committee today, and Wall Street applauded her comments in support of continuing the central bank's stimulus program. The Dow Jones Industrial Average (^DJI -0.11%) now sits at fresh all-time highs, having risen four of the last five sessions. The index tacked on 54 points, or 0.4%, Thursday, to end at 15,876. 

Home Depot (HD -1.77%) stock ended as the Dow's top gainer, adding 1.7%, to post its third straight day of advances. The consumer services sector outperformed the broader market today, a trend investors have gotten used to recently -- stocks in the sector have surged more than 43% in the last year. Home Depot's quarterly earnings are set to come out next Tuesday and, with the housing market booming, investors figure good things are in store for the home improvement retailer.

A retailer of quite a different ilk, E-Commerce China Dangdang (DANG) also saw its stock jump today, as shares surged 4.1% after an earnings report of its own. While the company announced a narrower loss than analysts were expecting, my colleague Rick Munarriz pointed out revenue growth below 20% is sluggish when compared to Chinese rivals. He has a point: earlier this week, fellow e-retailer Vipshop boasted sales that more than doubled from the same period a year before. It looks like Dangdang was only able to advance after setting the bar pretty low for itself. 

Lastly, shares of Millennial Media (NYSE: MM) tanked Thursday, losing 12% after a very disappointing quarterly report sent investors heading for the exits. Shares of this mobile advertising company have been wildly volatile in the past week leading up to yesterday's results. Optimistic investors even bid the stock up more than 6% yesterday in hopes of a bullish report. While revenue advanced more than 18%, margins fell, and losses expanded, making for an all-around disappointment. After all, even the revenue uptick was far below expectations: analysts were hoping for more than $67 million in sales, but Millennial Media posted sales of just $56 million in the period.