I've been saying for weeks now that you can't ignore the potential of online advertising.  I've said no less than a half a dozen times you should examine your existing marketing budget to see where funds could be shifted to online markets (if those funds are there already).  Maybe you've done it.  Maybe you haven't.  But for the sake of conversation, I'm going to assume you have.

So you've got your big stack of bills now, just ready to slide them across the table to some advertising company.  Now that you've got the money ready, you have to decide who's going to get it and how they're going to advertise your product or website.  There are literally thousands of places you could spend it.  Some big, some small.  The choice of where to invest ad dollars online can be daunting without some advice.

Advertising Age says those dollars are best spent with "The Big Online Four".  According to AdAge, Google, Yahoo, MSN, and AOL command the lion's share of online ad revenue.  In fact, says AdAge, the top 10 online companies account for more than 70% of that revenue (with the top 5 making more than half of it).

New companies are coming up with new technologies to try and wrestle some of those ad revenues away from the big guys.  Advertising Age talks about one of those companies in particular in their report.  Quantcast has created a system for measuring site visitor demographics deeper and more specifically than even the Big Four… for now.  For example, they're able to pinpoint specific audience segments of specific MySpace profiles.  Their approach is to be eventually able to offer advertisers a set of websites so specifically targeted at their audience that not even mass advertising on the big networks would be able to match the returns.

Even though a few companies hold most of the keys for now, it's still anyone's game.  New players and new games are popping up almost daily.  Keep an eye on the Big Four… but don't forget the up-and-comers, either.

Remember… every "big guy" was once a "little guy".