Search algorithms & popularity factors: link, social, click, blog, industry. Since modern search engines are concerned with popularity and not direct relevancy, & big firms up the price of text link buying beyond affordability...
"Not many sites can take you from the Design Council to Design Addict, from the Rural Studio to Worldstudio, and have it all make sense. Nate Burgos’s ever-evolving webliography is a smart portal to the ever-expanding universe of design"
links to knowledge sharing or knowledge management site; larger site is most comprehensive listing of web2.0 sites I have seen, organized into many categories; blogger is from Netherlands