Editor’s note: David Spitz is the vice president of product management & client services at ChannelAdvisor Corporation. This column is the latest in the Entrepreneurial Spirit series produced in partnership between CED and WRAL Local Tech Wire.

RESEARCH TRIANGLE PARK, N.C. – Pity the poor Internet marketer – these days, she could be forgiven for feeling a bit dizzy. Just when she got comfortable with email marketing and banner advertising, along came search engine marketing (SEM) and search engine optimization (SEO), a combined multi-billion dollar industry that just five years ago barely existed – an industry which, by the way, today accounts for about 40% of e-commerce.

And nowadays, it’s all about podcasting, blogging, RSS, getting “digged,” linkbait, not to mention the seismic shift towards Internet video… it seems like a never-ending stream of (faddish?) new media channels clamoring for attention and mastery. Which channels are real? Which will end up on next year’s “What’s Not” list? What’s the most effective way to leverage these channels at an effective ROI? It’s enough to give anyone a headache.

These days, everyone knows what banner ads and email marketing are. And most people, through their daily use of search engines like Google and Yahoo!, are at least vaguely aware of how marketers pitch their products through search (e.g., through sponsored links). But not everyone’s on the “Web 2.0” bandwagon just yet, so it’s helpful to lay out the landscape and define some terms:

Blogging: A blog (short for “web log”) is essentially an online, public diary or journal of sorts. There are literally millions of blogs out there – and not surprisingly, a much smaller number of worthwhile blogs. Many are personal blogs (keeping up with family, etc.), and some are industry-focused. A few blogs become very popular in particular circles because the author is considered authoritative on a specific subject matter, and these blogs are often the source of “scoops” or other news-worthy events, even before traditional news media.

This matters for a few reasons. First, getting one’s products or services discussed on a well-regarded blog can instantly catapult (or destroy) a marketer’s message; these blogs have thousands, or even tens of thousands, of loyal readers who trust the author’s credibility and who themselves often have sway in their respective markets.

Second, blogs tend to be highly viral in nature in that a “cluster” of blogs often exists for any given topic, and once one blogger “scoops” an interesting story, the rest tend to write about it, link to it, etc., exponentially driving up traffic and awareness.

Finally, search engines tend to weight blogs heavily due to their popularity and dynamic nature, and so product references by (and links from) a blog tend to drive up the coveted “natural” rankings of a marketer’s company or products in search engines. In fact, some less-than-well-intentioned authors can deliberately write inflammatory or controversial posts in an attempt to get others to link to their blogs, a practice known as “linkbaiting.” As you can see, nature abhors a vacuum.

And, of course, many companies have set up corporate blogs as a way to communicate with their customers, prospects, and communities.

The important thing about blogs, from a marketer’s perspective, is to keep them transparent and “personal” in nature, and to avoid (or disclose) conflicts of interest. Blogs have become elevated in consumers’ minds as quasi-independent sources of information and deserve different treatment from other pure marketing channels as a result. They should be informative, but not pushy.

RSS stands for “Really Simple Syndication” and is nothing more than a protocol allowing multiple ways for dynamic content – like blogs – to be “broadcast” to subscribers. Many consumers have RSS readers set up to track their favorite blogs, which is nice because they don’t have to visit each site individually to see what’s new.

RSS is also a nice way for marketers to reach the best kind of customer: one who’s opted in to receive commercial messages. A few leading marketers have successfully leveraged RSS as a way to publish product information, specials, and other communications to customers who’ve specifically asked to receive such information. American Express, for example, has been aggressive in its use of RSS feeds, offering subscriptions to topics ranging from travel to events to its Membership Rewards loyalty program.

In general, RSS for marketers can be thought of as email marketing “2.0” – it’s purely opt-in, free of spam, and as a result, a highly effective way to communicate with customers. There are a variety of providers who can help marketers leverage RSS, like FeedBurner.

Podcasting is what happens when blogging and RSS meet audio (in fact the underlying protocols are essentially the same). It’s just a way for multimedia content to be published to subscribers and was made popular, of course, by Apple’s iPod and iTunes software.

Podcasting as a marketing medium has yet to materially take off, however; it has yet to be proven that consumers want to subscribe to commercial audio messages (it’s much easier and faster to scan text subscriptions via an RSS reader than it is to listen to a set of audio ads), or have audio “pre-rolls” inserted into the audio content to which they’re subscribed. Plus, what’s the “call to action”? For consumers, there’s nothing to “click” on in response to an ad.

Video: As Google’s acquisition of YouTube demonstrates, it’s all about video now… except no one’s really figured out the right model just yet when it comes to Internet-based video marketing. A few marketers have had success with viral marketing campaigns – if you haven’t seen “Will It Blend?” on YouTube yet, take five minutes and have a good laugh (before you discover that this campaign helped BlendTec sell more Blenders in one weekend than in its previous best sales month ever!) – but aside from a few lucky breaks this isn’t really a scalable model for marketing. Will pre-rolls work? Will Internet consumers tolerate the traditional ad insertion model that propelled television for nearly a century? It’s hard to say.

So how does a marketer tie it all together?

An effective Internet marketing strategy will focus on three core variables: traffic, conversion, and cost. Without traffic, nothing else matters (traffic is the Internet equivalent of “location, location, location”), and so a marketer must continue to focus her efforts wherever consumers are found. Today, that’s still predominantly via search engines, social networking sites like MySpace and Facebook, and to a growing extent, blogs and RSS, and email marketing (especially opt-in house lists). It still remains to be seen how marketers will effectively leverage new media like podcasting and video, so marketers who aren’t on the bleeding edge might sit tight to see how those channels evolve.

As for conversion, marketers need to make sure their message is targeted, relevant, and drives consumers to a desired and actionable state. Marketers should ensure their products and services are easy to understand, easy to buy, and easy to service. There’s no greater sin in marketing than to capture an active, interested lead, only to make it difficult for that potential customer to get what he wants. Make it simple, eliminate unnecessary clicks and page views, and close early and often!

Finally, focus on cost. Each marketing channel, new or old, has unique cost considerations that should affect how a marketer leverages that channel. Is it a customer acquisition channel? Then what’s the target cost per acquisition? How do you allocate cost across multiple channels for a given sale? How do you track and measure these results effectively? Without an effective way to measure ROI, an Internet marketer isn’t making use of the single best aspect of Internet marketing: its measurability.

In the future, the “Long Tail” and leveling aspects of the Internet will in all likelihood continue to drive increasing fragmentation – fragmentation of sellers, consumers, products, and channels. While this may be great – ultimately – from an efficiency standpoint, it does make the Internet marketer’s job a challenging one indeed.