“You’ve got mail!”

Does that phrase bring back any fond memories for you?

Chances are good that if you were an early user of America Online (AOL) – like I was – then you still remember the thrill of getting a new email.

But today… It’s a different story, isn’t it?

Your email inbox is probably more flooded than you’d like.

Welcome to the intersection of marketing and technology. What was once new and exciting eventually becomes mature, saturated, and less effective. For example, email open rates are nowhere what they used to be 5, 10, or 15 years ago.

But don’t make the mistake of equating “less effective” with “not effective.” Sure, email isn’t as effective as it once was — but it’s still one of the most effective online marketing tactics available today.

A recent survey by ExactTarget shows that email is still the #1 way that consumers prefer to receive marketing messages, above social media.

My personal experience confirms this. Email marketing has been one of the most effective marketing channels in all the businesses I’ve started, managed, and advised over the past 8 years.

The big question is: How quickly should you change your marketing in response to changes in technology?

No doubt, there’s a ton of hype about social media marketing — and there will be even more as Facebook has its initial public offering (IPO).

As a result, many business owners feel compelled to jump on the bandwagon, abandoning “old-school” marketing tactics in favor of the newer, shinier options.

Here’s my advice.

1. Treat Your Marketing Like A Portfolio

You should think of your marketing investments like an investment portfolio. And, as with investing, you should allocate funds to different asset classes (e.g. a certain percentage to stocks, a certain percentage to bonds, etc) that have different levels of risk.

If “old-school” methods like cold calling, TV, radio and direct mail are working great for you, that’s great — stick with them. There’s no need to totally abandon what’s working. (And let’s be clear — by “working,” I mean getting a positive return on your investment.)

You might allocate at least 80-90% of your marketing budget to tried-and-true methods and 10-20% to more experimental, newer forms of media.

2. Go Where Your Customers Are

When it comes to experimenting with newer forms of media — like Facebook, Twitter, Google+, Pinterest, etc — there isn’t much value in beating your customers to the punch.

I recommend you use Twitter and Facebook if your customers are already on Twitter and Facebook.

But don’t feel compelled to use Google+ and Pinterest if your customers aren’t already there.

3. Always Look at the Numbers

The RIGHT reason for investing in marketing is return on investment.

The WRONG reason for investing in marketing is hype.

Don’t invest time, energy, and money into marketing on Facebook, Twitter, Pinterest and Google+ just because “everybody’s doing it.” In fact, “everybody’s doing it” is rarely a good reason for doing anything.

Again, let’s take an investment analogy. Would it be a good idea to buy a stock because “everybody’s buying it?”  Nope. That’s speculation, not investing — and that’s where most investors get into trouble.

Like a smart investor, you should remain focused on the fundamentals, and always make your marketing decisions based on the numbers.