Our clients are mostly large SEO agencies and online software vendors. We have a powerful and flexible online application with special features for managing multiple client accounts, but most of our large partners integrate our functionality and rankings into their own applications using our REST APIs. See responses to next question on which clients are ideal...

Large deal in the process of close: ADP (auto) Dealer Services (API)

LexisNexis Law Firm Marketing (API and app)
Yodle.com (API)
Acronym Media (API)
SlingshotSEO (app now, soon to be API only)
Volume 9 (API)
Morpheus Media (app)
SearchDex (app)
OrangeSoda (recently acquired by Deluxe Corp) (API)
HRmarketer.com (API)
Spark Internet Marketing (app)
Provide Commerce (ProFlowers.com, RedEnvelope, etc) (app)
ZocDoc (API and app)
TicketsNow (app)
Quiznos (app)
Levolor Blinds (app)
Enova Financial (app)
Total Beauty (app)

We have more than 20K direct+indirect clients, including a vast number of indirect brand names across the US.