Some companies are obviously great investments -- in hindsight. Yet for every stock out there screaming "buy me," others simply give us a nudge and a nod. How can we tell tomorrow's obviously great investments from the thousands of pretenders?

The stars' walk of fame
On Motley Fool CAPS, these opportunities can be found among our four-star stocks, companies that rank higher than most of the other 5,400 starred companies, but fall just short of a top ranking. While all the attention might be focused on their five-star peers, we can sift through CAPS to find four-star firms approaching greatness. Here are a handful of stocks that are approaching greatness.

  • BioSante Pharmaceuticals (Nasdaq: BPAX)
  • Codexis (Nasdaq: CDXS)
  • Endeavor Silver (AMEX: EXK)
  • Kodiak Oil & Gas (AMEX: KOG)
  • Limelight Networks (Nasdaq: LLNW)

Some of these names might surprise you. For example, drilling specialist Kodiak Oil & Gas unveiled a plan to clear the decks of debt and ramp up a drilling program for the year that's gotten a lot of investors excited. Almost great? Even familiar names can still offer some of the best opportunities. Perhaps we've just forgotten the potential they still hold.

BioSante Pharmaceuticals has been plowing away at developing a female version of Viagra. It's nearing the end of its phase 3 trials, and there's investor love in the air over the potential for the biotech to succeed where others like Procter & Gamble failed. Yet as the 170,000-plus CAPS members have chosen these companies as less obvious sources for tomorrow's great buys, let's see why they might merit your attention.

In the sight of greatness?
With backing from industry giants in the oil and pharmaceutical fields, tiny Codexis is looking to energize growth. Although it was spun off from Maxygen almost a decade ago, Codexis only went public last year, and it remains largely an unknown quantity. Its parent announced last November that it was shedding the rest of the stock it owned in the clean tech specialist, and opportunities for it to launch itself higher are in place.

Codexis uses naturally occurring compounds to make existing industrial processes faster, cleaner, and more efficient than current methods. Called biocatalysts, these enzymes and microbes initiate or accelerate chemical reactions, but have the drawback of not being as stable as chemically produced compounds as well as being expensive for industrial scale production. Codexis believes it has overcome these limitations and has the backing of industry giants such as Chevron and Pfizer.

Highly rated CAPS All-Star jackjjr is intrigued by its processes that target the oil and pharma industries, but Codexis remains an unknown quantity on Wall Street.

They are creating new innovative catalysts for clen energy and pharmasutcals. They are just getting started and could be a major money maker if their current work with Shell oil is sucessful.

With only a handful of CAPS members rating them, and having no analysts following, the All-Stars who have weighed in are unanimous in believing Codexis will beat the market. Head over to the Codexis CAPS page to provide a catalyst for outperformance.

Dirt cheap?
Considering Fed Chairman Ben Bernanke believes his quantitative easing policies are good for the economy because they've caused the stock market to go up, it's hard to argue with the opinion of Endeavor Silver CEO Bradford Cooke that "we're looking at the next wave down for paper currencies." It's probable though not even he thought silver would ratchet higher like it did, but with an innate ability to find new reserves and a top-notch production process from existing mines, Endeavor is positioned to ride the wave that will take silver even higher.

CAPS member greentree08 sees The Bernank as a good reason to expect Endeavor to shine even brighter going forward.

Silver is on the rise. QE is going to help silver continue to rise. EXK has had four consecutive years of beating annual growth estimates by 26% each year. They also have a low amount of debt.

Add Endeavor Silver to the Fool's free portfolio tracker and keep an eye on all the news and analysis that develops.

On the level
You might not have realized it, but the world has run out of IP addresses. The Internet Assigned Numbers Authority doled out the last batches of IPv4 addresses to the world's Regional Internet Registries. Each of the five blocks of addresses delivered contains about 16.8 million IP addresses, and now there are no more to assign.

Before you think the end of the Internet is nigh and we need to prepare for a Y2K-like meltdown, the world's ISPs, communications equipment makers, and content providers are preparing to move on to IPv6. As a matter of fact, Limelight Networks, Akamai, Yahoo! (Nasdaq: YHOO) and others will test the new system for 24 hours on June 8 to make sure there are no snags.

Limelight notes its content delivery services have been IPv6-enabled since 2009, so it's not worried about the conversion, and most people won't have to do a thing, though Windows XP and Linux users may have to do some tweaking (but Vista and Windows 7 users won't). It's probably because Limelight has been such an innovator that 90% of the CAPS members rating the content delivery leader believe it will continue outperforming the broad market averages.

Add Limelight to your watchlist, then head over to the Limelight Networks CAPS page and shine a light on your expectations for the future.

A great opportunity for you
Investor sentiment suggests these four-star investments still seem to be on their way to five-star greatness, but it pays to start your own research on these stocks on Motley Fool CAPS. Read a company's financial reports, scrutinize key data and charts, and examine the comments your fellow investors have made all from a stock's CAPS page.

Sign up today for the completely free service and let us hear what you have to say about the great and almost great companies that interest you.

Pfizer is a Motley Fool Inside Value selection. Akamai is a Motley Fool Rule Breakers pick. Yahoo! is a Motley Fool Global Gains recommendation. Chevron and Procter & Gamble are Motley Fool Income Investor recommendations. The Fool owns shares of Maxygen. 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. 

Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his portfolio here. The Motley Fool has a disclosure policy.