What's better than momentum? Mo' momentum. Let's take a closer look at five of this past week's biggest scorchers.

Company

Dec. 13

Weekly Gain

Twitter (NYSE:TWTR)

$59.00

31%

Model N (NYSE:MODN)

$10.88

27%

E-House (NYSE:EJ)

$13.90

20%

Groupon (NASDAQ:GRPN)

$10.24

13%

Facebook (NASDAQ:FB)

$53.32

11%

Source: Barron's.

Let's start with Twitter. The social-media darling soared after once again catching Wall Street's attention. RBC Capital Markets analyst Mark Mahaney raised his price target dramatically -- up from $33 to $60 -- after assessing that advertisers plan to spend more on Twitter's marketing platform in the near future.

Model N broke into double digits on Friday for the first time this quarter. The provider of revenue management software solutions announced a global price management offering for biotechnology companies. Its CEO is also helping out Model N's finances by requesting to that his annual salary be reduced to just $1 for fiscal 2014.

E-House kept building to its gains after Goldman Sachs issued a bullish opinion on the Chinese provider of real estate services. Goldman Sachs doesn't really see the spike in housing prices as a bubble that the government will want to pop. Shares of E-House have more than tripled in 2013.

Groupon was the real deal for investors after receiving a pair of bullish analyst notes. Morgan Stanley and Wells Fargo waxed positively on the daily-deals leader. Morgan Stanley reiterated its "overweight" rating, impressed by Groupon's advancements in mobile and its ability to make the process easier for deal buyers. A day later, Wells Fargo chimed in with an upgraded rating on the shares. 

Facebook moved higher after it was added to the S&P 500. The index typically waits as long as a year for a prolific IPO to gain some seasoning before being added to the widely tracked market gauge. Facebook took a bit longer than that. The move finds huge index funds that mirror the metric having to buy into Facebook