More than 100 leading marketers from companies such as Merrill Lynch, Kimberly-Clark, Women.com and autobytel.com attended IIR’s Marketing to Women on the Web event last week. Here’s a quick summary of the top five lessons we learned there:

1. Women are a POWERFUL economic force in the US, controlling nearly 85% of the nations’ household income ($3.5 trillion year!) This pocketbook power is beginning to translate into ecommerce sales as women dominate the Web demographically.

2. “Simply painting your brand pink is NOT an effective strategy for appealing to women online.” Marti Barletta, President Trend Sight Group

3. Online marketing strategies that appeal to women tend to also appeal to men. The converse is not true. By targeting men online you won’t also bring in a female audience. So in essence it’s more cost-effective to target women because then you are appealing to both sexes!

4. Women find online community hugely compelling, especially when community sites or discussions are targeted to a particular niche demographic. AsianAvenue.com and BlackPlanet.com have both registered about one million predominantly female members each.

5. Targeting women by life stage segments such as single or mother of young children is more effective than targeting by age alone. A married mother of 45 often has more in common with a married mother of 25 than she does with her single 45-year old peers.