If you are in the business of attracting and turning web visitors into customers, there are two resources that offer incredible value.
Hubspot the Cambridge based inbound marketing company has many free tools, resources and webinars that are very valuable for companies looking to improve their web marketing presence. Web Site Grader and Twitter Grader are fun as well as informative. They also provide a lot of useful content on blogs, white papers, free Webinars and videos. Maybe the best lesson is, the company itself is excellent proof of the power of it's own concepts. Their growing presence in the webshpere is an example to follow.
Startonomics is a one day workshop on web marketing co-organized by Dave MCclure and hosted by Deal MakerMedia. Even though it was held in San Francisco, we on the East Coast can still attend (virtually) as all the sessions and slide decks have be posted via video as well as Slideshare. This is a must view for anyone hoping to gain insight on how the most experienced consumer web marketers have honed and practiced their craft.
So much information is available to help entrepreneurs learn and navigate the startup waters, but these two stand out among the rest.