Things have been looking up for Pandora Media (NYSE: P) lately.

Shares of the music-discovery website have climbed in each of the past seven trading days, gaining a whopping 46% in that time.

Cynics will rightfully argue that Pandora is still trading below the $16 price it went public at four months ago, but momentum has been on the side of the bulls these days.

Pandora has never had a problem winning over growth investors. The service's popularity is undeniable, serving up 1.8 billion hours of listening in its latest quarter. Revenue soared 117% during the second quarter, and Pandora even managed to post a rare quarterly profit on an adjusted basis.

Last week also treated believers to a few encouraging news items breaking Pandora's way. Hyundai, for starters, revealed that Pandora will be a free standard feature on its new Veloster car line.

Sirius XM Radio (Nasdaq: SIRI) isn't being left out in the cold here.  All Hyundai cars come with XM receivers. However, the ability for smartphone owners to seamlessly stream the free music-discovery site through their car speakers will make it tempting for the car's young target audience that doesn't want to spend roughly $15 a month for premium radio on top of the smartphone bills that they're already paying.

In a nutshell, Hyundai joins Ford (NYSE: F) and Toyota (NYSE: TM) as automakers promoting easy access to Pandora in many of their 2012 models.

Visibility has never really been a problem for Pandora. Viability is the biggest concern, especially since so much of Pandora's revenue goes right out to the record companies.

Well, Pandora's also gaining ground on that front.

September data from radio ratings tracker Edison Research shows Pandora making some serious inroads in several key markets. The local emphasis in Pandora's press release touting the gains is by design, since area advertisers will need to reach out through Pandora if they want to access the web-savvy radio listeners that have largely moved on from terrestrial broadcasts.

The market is getting more competitive. European fave Spotify washed ashore earlier this summer. Clear Channel (OTC: CCMO) re-launched its iHeartRadio app last month with a Pandora-like upgrade. Sirius XM is rolling out Sirius XM 2.0 this quarter, upgrading its already-popular service.

However, after a brutal first few months as a public company, Pandora investors are finally singing a merrier tune.

If you want to see how the premium and streaming radio wars play out, consider tracking Sirius XM Radio and Pandora Media through My Watchlist.

The Motley Fool owns shares of Ford. Motley Fool newsletter services have recommended buying shares of Ford. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

Longtime Fool contributor Rick Munarriz calls them as he sees them. He does not own shares in any of the stocks in this story, except for Ford. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.