The largest Internet companies in Chicago

I spend a few hours a week meeting with people who are either a) looking for a job at an Internet company or b) looking to start one.  I always run through a list of both large and interesting (sometimes they are actually both!) Internet companies.  My definition of an Internet company is a company delivers the majority of their service and product over the Internet.  I will create a separate list of folks like United Airlines, Hyatt and Sears who are using the web in significant ways to drive sales. My bias with this particular list is toward the "consumer Internet" because I know less about the agency, consulting and b2b space, so please add some comments about who you would add.

The Biggest "Pureplay" Chicago Based Consumer Internet Companies (100+ employees)

1. Orbtiz 
2. Careerbuilder
3. Ticketsnow
4. OptionsExpress
5. Tribune Interactive
6. Travel Click
7. Classified Ventures
8. Shoplocal
9. Think or Swim
10. Peapod
11. Q Interactive
12. Legacy.com
13. Groupon (super hot!)
14. Total Attorneys (sizzling!)

The Mid Size (20-100 employees)

1. Threadless/Skinny Corp
2. iExplore
3. Sittercity
4. Vibes.com
5. GrubHub.com
6. Viewpoints.com

The Small (but mighty!) (1-20 employees)

1. AnalyteMedia
2. Lifesnapz /Timeline
3. Txtful.com
4. Menuism
5. Everyblock  (sold to MSNBC?)
6. OneWed

The biggest B2B Chicago based Internet companies

1. Surepayroll
2. Comscore
3. Savo Group
4. Performics (now owned by Publicis)
5. Feedburner (now owned by Google)
6. LeapFrogOnline

Web Development Shops

1. Alpha Zeta
2. Design Kitchen
3. March First
4. VSA Design
5. Collosal Squid

Interactive Agencies

1. Pending