Obviously it is very hard to run just a SEO company, better to promote your services as SEM services, cause you need to expect many requests for pay per click management or mail campaign or banner ads.
Internet marketing is simply the art of driving qualified traffic to a website, so any source of traffic should be important for internet marketing company.

Did you hear about web 2.0 ? if you are in the internet marketing better to answer yes, with web 2.0 the web transform from static websites to interactive websites, and those websites like Digg, Stumbleupon, Myspace .. etc now enjoying tons of daily traffic which most likely will be sent again to many websites on the net. Again as an SEO you need to care about that, it is enough to know that hitting the first page with Digg may drive you more than 10 000 unique
visitors/day and so on for other mediums where being on the top ten spots will drive you similar amount of traffic. So make sure to have qualified content and then add your website to those website and wish to get the traffic !

Getting some buzz from social media will help your link building campaign as well, since many journalist and bloggers like to write about website on the first page with Digg or Delicious