A few sites listed as recommended viewing:
Points out forum threads and other links that may be particularly interesting for SEOs.
Pretty popular SEO/IM site, but I thought I'd share anyways. Provides a plethora of information, news and tools for internet marketers and SEOs.
Handy tool that lets you spy on your competitors (keywords they use, ad campaigns, etc). Basic use is free, but it costs money for all of the features.
While it sort of works like an upload service, it's sole purpose is to allow you to send email attachments up to 300 Megabytes in length. Very nice to have when traditional email services give you small caps for attachment sizes.
This is historical archive of most of the internet that keeps copies of nearly all web sites, with links to the dates they were updated. I use it a lot to research the history of interesting companies.