Wednesday’s post reminded me of another voice people often trust, but really shouldn’t: Wall Street analysts.

A funny thing happened to one of the stocks in the Cabot Green Investor portfolio last month.

All of the movement toward renewable energy and slicing carbon output represents a profitable opportunity for investors. One Green stock I particularly like because it has a dominant position is a product that is used in solar and wind power systems as well as hybrid vehicles.

Oil and gasoline prices, as you likely have noticed, have been easing lately, even as we’re in the midst of what energy industry hands call “the summer driving season,” the period in which people tend to drive a lot for vacations and weekend visits and in general give energy traders reasons to bid the prices up. It’s hard to believe that one year ago a gallon of gas averaged $4.06 nationally, according to the Energy Information Agency. That was the highest weekly average since 1990–the low being early March 1999, when gas cost a mere 89 cents. Last week, the average price was $2.56, down from the year’s high of $2.60 a month earlier.

I bring up gas prices because as editor of the Cabot Green Investor, I have noticed that there is a fairly popular–and false–idea about the correlation between gas prices and Green stocks. The idea is that as the prices of oil products drop, there must be a decrease in interest in hybrid cars, solar panels and the like.

...If you follow the stock market, you already know the stock of Whole Foods Market (WFMI) has been a big winner due to this trend for much of this decade. In fact, in recent years, sales of organic products overall were rising 25% a month (!) until the economic turmoil of last autumn. Naturally, because organics are generally pricier, that rate of growth dropped. Yet while pundits expected the recession to be the death knell of the widespread move to organics, it hasn’t been.

The organic and natural foods market segment is still seeing growth of 1% to 5% a month, compared to 0.4% annual growth for groceries at large. What appears to have happened is that consumers haven’t cut back heavily on organic groceries, although they have shifted more to bulk organics. Instead, they have cut back more on restaurant dining.

As editor of Cabot Green Investor, I love uncovering companies with a firm hold in a niche area of Green, like Fuel Tech (FTEK), which tend to hold up well in difficult markets while benefiting from sustained uptrends. I also love getting subscribers into growth stocks that benefit greatly from a bullish market, like the one we find ourselves in now. Last July, I identified Green Mountain Coffee Roasters (GMCR) as the next potentially great stock.

Doomsaying is a tricky business. In the late 1970s, when commodities were king, technical analyst Bob Prechter correctly predicted the implosion of the commodity bull market and a “’super cycle’” bull market in equities. His eerily on-target prediction made him an investing superstar. Unfortunately, he then predicted the 1990s would be a severe bear market for stocks, capped by a prediction that the Dow would fall to 800 at the start of this decade.

Right now, Peter Schiff, president of Euro Pacific Capital, is the doomsayer du jour. Schiff, as you may be aware, takes credit for predicting the market crash of last autumn in his book “Crash Proof: How to Profit From the Coming Economic Collapse.”

Nahant, the town where I live, is the smallest in Massachusetts at just 1.2 square miles. It consist of two islands -- Big Nahant and Little Nahant -- connected to the mainland by a two-mile road paved over the hump of an arcing sand dune created hundreds of years ago by the tides. Having lived here for just a year, I can say there's a lot to like. Just about every house is a five-minute walk from a beach, taxes are bearable, it's safe and it has lots of playgrounds--things that matter more to me now that my wife Jeanne and I have Lila, our nine-month old baby.

Nahant is also breezy in the summertime, which keeps the weather from getting as hot as on the mainland, where the Cabot offices are located. The downside is in autumn and winter when that idyllic summer breeze turns into an often-relentless wind. Boston, just a few miles south, is in fact the windiest city in America as measured by average daily windspeed. So while I have been skiing at Lake Placid when it's 30-below, traipsing on glaciers during Iceland's enduring night and sporting an agonizingly thin suit the day it snowed on Opening Day at Yankee Stadium, I have never been so cold as during my five-minute morning walk to Richard Tresch's economics class my freshman year at Boston College. The wind is the only real downside to my adopted home.

Throughout the 13 years he was steering the Magellan Fund, Peter Lynch became known for his philosophy that you should invest in what you know. In his 1993 book, "Beating the Street," he discussed how he built Magellan from a $200 million fund to a $14 billion fund in a little more than a decade. The philosophy Lynch wanted to drive home to individual investors was that you should buy companies that you are familiar with. In Lynch's case, he liked the "tasty tacos of Taco Bell," so he added the then-unknown chain into the portfolio; his wife loved the convenience of L'eggs hosiery, so he bought shares of Hanes.

Buying what you know has long since become a bit of Gospel among a large segment of investors--after all, if it worked for Peter Lynch, it should work for you. It's not a bad idea--certainly if you feel strongly about a company and have what you think is pretty decent insight into its products and market, then you can do all right. I know a few creative types who did quite well buying Apple Computer stock when it was well under 20 in the late 1990s.