I am not sure why, but when you say extreme marketing I actually think of bold, most successful ad/marketing campaigns rather than out-of-order behavior or ad messages. Or perhaps a classic case of overdoing your marketing efforts.
For example, everyone who has been around for a while will probably remember these:
Media Temple - their support of the web design industry has won hearts of many many graphic professionals. To me, Media Temple almost rhymes with a web designer.
When 1&1 Internet was launching operations in North America, they came to the market with an offer few firms could beat: 3 years of free professional web hosting. Not 2 months, not 1 year - 3 full years. Such a bold move saw the company sign-up over 10,000 account per month, 3,000+ of which were paid clients of other companies switching to 1&1. I certainly don't know how many clients switched to paid hosting after 3 years were up, but the company sure got cheap attention with dozens of conversations started in most hosting forums.
To this day 1&1 Internet continues its extreme marketing with a very heavy print ad campaigns in leading IT magazines, such as eWeek. Rarely do I see an issue without 2-6 pages of full-page ads.
In a similar move, FastHosts.com has been offering free reseller hosting free for a year.
Site5 - when they launched a $5000 website re-design contest, the news has hit the airways and the company has received enormous attention.
CI Host's major gifts with every hosting account. They no longer practice the same policy, but boy was the offer seductive!