This article is part of our  Rising Stars Portfolio series .

In late April, I steered investors following my technology-oriented Rising Stars portfolio toward Google (Nasdaq: GOOG), now that the search giant has fallen out of favor.

Since 2008, continuing high growth rates and a stagnant share price have compressed Google's P/E ratio by more than half. In mid-2008, the company sported a P/E ratio hovering around 40; today, it's less than 20.

The fallout from Google's continuing decline has even hit my own portfolio. Since that late April buy, the stock has fallen by 7%. However, I'm not scared away by short-term declines in Google's share price. In fact, today I'll use its decline to pick up more shares on the cheap.

The Google bull case
I've already laid out my basic thesis for why Google is a good value in my original buy recommendation. Today, I'll list and rebut several points of concern weighing on Google's share price.

97% of Google's revenue comes from advertising
This most fundamental complaint results from a huge misunderstanding between what shareholders expect and what Google is trying to achieve.

Investors are constantly bombarded with new projects coming from Google: Gmail, Docs, mobile operating systems, cloud music -- the list goes on and on. Surely, with all this spend, either Google is wasting fantastic sums of money, or it should be generating more revenue from these endeavors, right?

I'd disagree. Take Gmail, for example. When it first came out, varying critics groused that it offered too much storage and was an expensive distraction. To that point, it was viewed at the time as another means for delivering ads targeted to users. However, over time, the real importance of Gmail has surfaced.

By getting users to log into Gmail, Google has you logged into a unique identity that it can track; this builds up a previous search history that delivers more relevant search results. Google can also build future social elements upon this base, among other uses.

Like many of Google's other endeavors, Gmail was never supposed to be a moneymaker on its own; its true power lies in broadening Google's search moat. Likewise, Google doesn't directly generate revenue from its Android operating system, despite significant development expenses. Believe it or not, that's a savvy move on Google's part.

By giving away the operating system, Google has made Android the dominant mobile platform. In the long run, controlling the mobile platform is more important to Google than generating lower mobile licensing fees. By getting users to create Google profiles that feed it location data, and assuring its place at the center of search on mobile devices, Google will ultimately make its search more powerful and targeted.

With online advertising comprising just a small portion of advertisers' total spend, improving relevancy and targeting users more adeptly don't just help Google compete better against Microsoft's (Nasdaq: MSFT) Bing and other search engines. They also let Google command better fees for advertising for key terms. Thus, Google's simultaneously investing in key areas to secure its competitive position and increasing its addressable market.

Google's failing in key growth markets
I'm going to come right out and say it: The battle for China is over. Google is hemorrhaging market share, with the latest reports showing Google's share of search approaching single digits. Baidu (Nasdaq: BIDU) is becoming more entrenched as China's dominant search engine by the day. Likewise, Yandex (Nasdaq: YNDX) is profitably dominating the Russian market, while Google plays second fiddle.

Both these losses hurt, but they don't destroy Google's pedigree as a growth stock. The company remains dominant in the other BRIC countries -- India and Brazil. Also, we tend to think of markets like search in a winners-and-losers framework. However, I believe multiple winners can emerge. Feeding off continuing growth of search advertising in developed markets and emerging-market demand from countries like India and Brazil in coming years, Google can easily grow into its current valuation. Likewise, while it's more pricey, there's a clear path for Baidu to grow into its own heady valuation by serving up ads to Internet-loving Chinese consumers.

As someone who has bought Google, I'd rather see the home team capture the Chinese market. But even if Google's largely ceded the contest there, the company's growth prospects remain alive and well.

Final thoughts
Given my continuing belief in Google's ability to grow its search moat, and my admiration for its adept mobile strategy, I think the company is just as good a buy as it was two months ago. But now, I get the added bonus of buying shares for 7% less. For the reasons outlined above, I'll be adding two more shares of Google tomorrow. In the long run, I think its competitive positioning is extremely strong. At today's prices, the Mountain View search giant could reward shareholders richly.

To stay updated on all things Google, follow my Twitter feed, where I post new articles and thoughts on the company and broader technology trends. Alternately, add Google to My Watchlist, which will keep you up to date on all of the search giant's newest developments.

Eric Bleeker owns shares of no companies listed above. The Motley Fool owns shares of Google and Microsoft. Motley Fool newsletter services have recommended buying shares of Microsoft, Google, and Baidu. 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.