You've seen him in the grocery store checkout. Four years old. He wants a chocolate bar. Now.

He pulls on his parents' clothes, jumps up and down, whines, gets louder, then goes ballistic, screaming and wailing and thrashing about. You've also experienced the same thing online with annoyingly intrusive ads. You have to put up with the kid and the ads, right?

The delightful child is a subject for another article in another publication, but the ads I can address. Besides, advertising is much more challenging than child rearing.

Online advertising follows the same basic rules as advertising in other media. It is important to define and target a specific market, geographically and demographically, and find a site or publication that potential buyers frequent.

If your Calgary-based business wanted to target other business owners in Calgary, for instance, you could choose the Alberta edition of this publication. Would advertising on the Alberta edition online generate the same results? "Maybe, but nobody knows," is the answer.

Although you would expect that Albertans would read the Alberta online edition, that is not necessarily the case. Nobody knows how many readers are from Calgary, Alberta or even Canada, although companies claim to know this, and get well paid to tell you.

There is really no way to accurately know or track who visits a website when destination sites, measurement companies and media sellers all disagree on the numbers and data-collection methods are antiquated.

The Interactive Advertising Bureau (IAB), a standards and practices company that represents more than 300 interactive online advertisers, asked the two major web traffic-measurement companies, comScore Inc. and Nielsen//NetRatings, to submit to an outside audit to find out why the two companies report different audience sizes for the same websites. After quite a bit of pressure, both companies "committed to timetables for the auditing of their technologies and processes by a third-party auditor," according to an announcement from IAB last month.

IAB CEO Randall Rothenberg writes: " Imagine my surprise when I came to the IAB and discovered that the main audience-measurement companies are still relying on panels - a media-measurement technique invented for the radio industry exactly seven decades ago - to quantify the Internet."

In the open letter, he laments the "flawed media-research methodologies" of traditional media and "phantom metrics, such as 'pass-along readers,' that add shadowy bulk to audiences."

So, nobody can pinpoint geographically where readers are, and nobody knows anything about these people with any certainty. This makes it difficult to target your market, doesn't it?

So, how do you choose a site for your online ad? Again, define your market and go where they shop or browse online. If you sell luxury items, then advertising on a site where designer jewelry is sold would make sense. If you want to target Canadians, then pick a .ca site.

A Vancouver mortgage broker may do well to advertise on a Vancouver real estate site because at least a portion of visitors will be needing a Vancouver mortgage. Armed with the knowledge that there will be visitors outside your target market (geographically and demographically) you should count on and pay for only a fraction of the hits to these sites. It is like using a blunderbuss to hit your target instead of a laser.

Search engines such as Yahoo or Google are the most common places for online advertising. "AdWords," Google's flagship advertising product, was launched in 2000 and is its main source of revenue. AdWords offers pay-per-click (PPC) advertising, and site-targeted advertising for both text and banner ads.

If you want your ad to appear on a Google search, you choose a list of words that relate to your company. When someone does a Google search, for example, for "university" and "essay," he or she gets 52,800,000 hits - and 17 paid-for Sponsored Link ads from companies hoping for clicks through to their websites.

The order of paid listings depends on other advertisers' bids (pay for placement or P4P) and the "quality score" of all ads shown for a given search. Google determines the quality score, based on, among other things, how many clicks an ad gets and its relevance.

The quality score is also used by Google to set the minimum bids for an advertiser's keywords: More popular = more expensive. Even though ads are priced at pennies per click, the costs add up quickly without a proportionate increase in business.

And that is something to keep in mind: People who buy online are more inclined to buy things that are deliverable online as opposed to items that have to be shipped, and online advertising works best if you can deliver immediately (music, software, images, service).

There are things you should know if you have a "screamer" online ad. Intrusive ads are just a step above junk mail and are often treated that way. Flashing, popping, blaring ads often cause a backlash and generate negative feelings, so avoid choosing them to represent your company.

If you do, be aware that your ads may not be seen by the vast majority of surfers because most browsers have built-in pop-up blocking (look in the preferences for the checkbox) that prevent them from functioning.

For more thorough ad blocking, there are many programs available such as Ad-Aware, Ad Blocker Pro and Super Ad Blocker to name a few of the dozens on the market. Apple Safari on my Mac with a CSS filter is successful at blocking about 95 per cent of ads, so advertising successfully is a constant battle and the ones that get through are mostly ignored anyway.

And that is a fact of life. Most of us try to overlook any ads that manage to squeak through the technology linebackers. But try as we might, online banner ads (not the screamers, though) do have a subtly positive effect, for a short while at least.

In June's Journal of Consumer Research, a study of online banner ad exposure revealed some interesting results:

* repeated exposure to a product via banner ads generates a positive feeling toward that product

* stimulus that's barely perceptible can enhance a person's feelings toward what's otherwise a neutral object

* seeing an ad many times has no negative effect, and

* banner ads may provide a valuable function in fostering familiarity even if those who view them never click through to the source of the ads What this basically confirms is that online banner advertising for awareness generates a positive response. It does not compel a reader to buy, but if your ad is not annoying it does make him feel warm and fuzzy about the company for a time.

Web portals, online sites with a large readership, are often also real-world publications (newspaper, magazine, television channel).

They are often effective places for banner advertising. They sell ad space in IAB-standard sizes using the same approach as traditional media, and guarantee impressions per mil, click-through stats (i.e. 15 per cent) and even relevancy targeting.

If they create the ad for a fee and host it, they also provide their own tracking but, as you have read, the accuracy is highly questionable.

Keep in mind that the return for online advertising is much lower than regular media, so impressions and clicks do not translate to sales the way other media do, but the brand association is a good thing. If the portal has the right demographic then you can ride their coattails with your brand.

I'd negotiate rates for online at the same time as buying other media, because it's easier for them to almost give away online space. Make good use of it by rewarding clicks through with coupons or contests in exchange for data (contact info).

Online advertising is really no more effective than billboards along busy highways - good for awareness but not good for generating direct sales.

Lots of people will see them, but only a minuscule number will act as a result. Perhaps that is all we can hope for.

Well, that and for the parents of the screamer to remove him from the scene.

(Brenda McMillan can be reached at mcmillan@businessedge.ca)