Viable Threat to Google Adwords Emerges
gigaom.com
gigaom.com
- Vendor lock-in - it's easy to swap out one set of ads for another.
- Positive network externalities - there aren't (big) network effects involved in ads.
Sure, there are some scaling issues, and some issues with regards to determining what the page is 'about', but those don't seem like insurmountable problems for reasonably large companies to deal with.