GRPs -- gross rating points -- are coming to online advertising, and I think it's a good thing. TV ad measurement giant Nielsen recently announced a new online campaign ratings product for Web ads that will include GRP measurements, broken down by basic demographics, much like what the company offers the TV industry.The notion of bringing GRPs to Web advertising is not a neutral topic. Many in the online ad industry have openly resisted and fought against the importation of "old" measurement metrics into the online world, fearing that linear media metrics would "understate" what makes online different and better than other media channels. Fellow Spinner Jason Heller wrote a very good column on the topic earlier this week, but I believe this the issue is so important I want to address it in my column today as well.Here's why GRPs will be good for online ads:Improve brand-friendliness of online ads. The online world is great when it comes to providing advertisers with direct marketing metrics. We have click rates, mouse-over rates, open rates, cost per action and any number of other direct measures. For brand advertisers and those focused on "mass awareness" we don't have much more to offer than measurements of impressions, unique users and average frequency, and the last two are highly suspect and skewed given growing cookie deletion rates. (Although there are services like Vizu that survey user awareness and attitudes for traditional brand metrics.) Understanding how much of the total online audience is being reached, and how the impressions were distributed by age and sex of users, are metrics brand advertisers know and value. Speaking their language can only help online attract more of their dollars.More comparability. Whether we like it or not, the majority of all ad spending in the U.S. goes to television. TV ads are measured with GRPs. The more that online media can do to be measured in a comparable way to the rest of the ad budgets, the better it can be valued -- and, by extension, the more likely it will get its full share of spend relative to the audiences it can deliver.Enables complementary Web and TV programs. Not only will GRPs make online ads more comparable to TV, but it will make it easier for media owners to create, price and sell complementary packages of online and TV media. For example, with GRP metrics, it will be much easier for TV networks to sell bundles of TV and online ads and measure the package in total GRPs delivered.Puts audience front & center. Online has not necessarily helped itself by leading with the click, click rates, and cost per click. Unfortunately, way too much online advertising is bought, optimized and valued on click-based metrics. Adding metrics like gross rating points and relative demographic reach should help advertisers focus more on the audience reached and a bit less on whether they are members of that elite (and unusual) club, the Natural Born Clickers.Doesn't mean the Web will lose its unique metrics. Adding GRPs to the online ad measurement doesn't mean we will lose those metrics that are unique to online, and which make it special, such as interactivity, dynamic addressable messaging and impression and user-level direct measures. They are not mutually exclusive to audience metrics like gross rating points and target rating points.Will this be the final word on new online ad measurements? I certainly don't think so. We still need to address the relative impact of an impression in different media. As we all know, an impression on the Web is as different from an impression on radio as is an impression on TV. The industry has grappled with the notion of defining "engagement" for well over a decade with no success and little progress. I don't expect major advancements here for years, but I do hold hope that we will someday find a way to tackle this issue.What do you think? Will GRPs be good for online advertising?