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.

Stocks continued their upward trajectory today, with the S&P 500 (^GSPC 0.87%) climbing to a new record close on follow-through gains after last Friday's surprisingly strong employment report. Even though various Fed officials called for an accelerated pullback from quantitative easing, positive news from several stocks heartened investors, with Twitter (TWTR), Sysco (SYY 0.77%), and DaVita HealthCare Partners (DVA 3.68%) among the top performers on the day.

Twitter jumped 9% to trade at its highest level since its opening day of trading. The social media giant has started taking steps toward more effectively monetizing its popularity, giving advertisers better tools to create ads tailored to individual users. Although the measure could well raise the usual spate of privacy concerns, taking maximum advantage of available data will be crucial in driving ad traffic and revenue to Twitter. Questions about the company's valuation persist, with valuations raising concerns about new irrational exuberance in social media, but now, it looks as though Twitter will have a chance to prove naysayers wrong if it can execute on its latest offerings.

Sysco climbed almost 10% after announcing it would buy privately held US Foods in a deal worth about $3.5 billion. The move should help Sysco reenergize its growth, which had been flagging in light of mixed conditions in the restaurant industry and greater competition from specialists in natural and organic food distribution. Sysco will use stock to pay for most of the buyout, and it will also take on the commitment to repay $4.7 billion in debt, which could threaten its credit rating. But the deal could boost its annual revenue by almost half, giving Sysco quick growth at a fairly reasonable price.

DaVita picked up 7%. The company held its Investor Day today, pointing toward the opportunities both on its DaVita kidney-care side of the business and with the medical group and affiliate physician networks that make up the HealthCare Partners segment. The company will take this week to highlight the benefits of allowing dialysis patients to keep working, pointing to health and psychological benefits. But in the long run, gains for DaVita stock will rely on both sides of the business in order to drive strong future results.