The best 'quality' knowledge resources for online marketing

The internet is over cluttered and there are hundreds of sites and portals out there on the web with varying info on best practice re: online marketing techniques. However, after over a year analysing a few (through newsletters and webcasts and 'free' white paper access), I'd like to share the following, which I have found the most useful - if you are a aserious online marketer i'd sign up with them and get involved asap!

1. HupSpot - www.hubspot.com (USA)

2. B2B Marketing Magazine - www.b2bm.biz (UK)

3. Marketing Profs - www.marketingprofs.com (USA)

4. Linked In - www.linkedin.com (Select 'Groups' and type in your online marketing criteria in the 'find group' search field)

5. Any Google Product - www.google.com/products

6. E-Newsletters from various international marketing associations and their official, affiliated journals/magazine.

Eg. CIM UK (The Marketer - www.themarketer.co.uk) and;

American Marketing Association - www.marketingpower.com etc.

Search - goes without saying:

www.google.com

www.wolframalpha.com

www.cuil.com

If you really have to:

www.bing.com

www.yahoo.com

Please feel free to add to the lists above, as I'm certain there are more 'quality' sites.