In the past we also derived a significant amount of revenue from referral fees paid to us based on leads generated by our online platforms that are delivered and sold to third parties. In early 2012 we began directly servicing most of the Medicare leads we generated as a health insurance agent, while significantly reducing the number of Medicare leads we sold to third parties. As a result, our lead referral revenue declined significantly in 2013 compared to 2012. To the extent that we assist in the sale of Medicare-related insurance plans as a health insurance agent, we generate revenue from commissions we receive from health insurance carriers, rather than one-time referral fees we receive for the sale of Medicare leads.
We expect our marketing and advertising expenses to increase in absolute dollars in 2014 compared to 2013 due primarily to increases in submitted individual and family plan applications from our marketing partners and in our Medicare-related online marketing and advertising expenditures during 2014, including paid keyword search advertising.
In order for us to offer and sell subsidy-eligible health insurance plans on our websites, we are required to meet certain conditions, such as compliance with standards for display of health plan and related information; providing consumers the ability to view all subsidy-eligible plans offered on the state’s exchange; displaying all subsidy-eligible health plan data on the state’s exchange; and providing a mechanism for consumers to withdraw from the application process to the state exchange. We increased our technology and content spending throughout 2013 in order to increase functionality to meet the conditions required to offer and sell subsidy-eligible health insurance plans and to enhance the user experience. We expect that technology and content spending will be impacted in future years by additional infrastructure necessary to maintain compliance with these conditions.
Cumulative balances at December 31, 2012 and 2013 consist of shares repurchased in connection with our stock repurchase programs announced on September 10, 2012 and March 6, 2013, as well as a previous stock repurchase plan announced in 2011, 2010 and 2008.
Additionally, in preparation for the Medicare annual enrollment period, and to a lesser extent the initial open enrollment period for individual and family plans, we begin ramping up our customer care center staff during our second and third quarters to handle increased volume of health insurance transactions during the fourth quarter. Accordingly, our customer care center staffing costs are significantly higher in our third and fourth quarters compared to our first and second quarters.
On January 1, 2011, 2012 and 2013, the number of shares authorized for issuance under the 2006 Equity Incentive Plan was automatically increased pursuant to the terms of the 2006 Equity Incentive Plan.
For tax return purposes, we had net operating loss carry forwards at December 31, 2013 of approximately $9.1 million and $70.9 million for federal income tax and state income tax purposes, respectively. Included in the state net operating loss carry forward are unrealized state net operating loss deductions resulting from stock option exercises of approximately $59.4 million. The benefit of these unrealized stock option-related deductions has not been included in the deferred tax assets table above and will be recognized as a credit to additional paid-in capital when realized. Federal and state net operating loss carry forwards begin expiring in 2023 and 2016, respectively. The federal net operating loss carry forward is subject to an annual limitation of approximately $2.5 million due to section 382 of the Internal Revenue Code. Approximately $2.5 million of the state net operating loss carry forward is subject to an annual limitation of approximately $0.1 million due to section 382 of the Internal Revenue Code.
For each of the years ended December 31, 2011, 2012 and 2013, we had securities outstanding that could potentially dilute earnings per share, but the shares from the assumed conversion or exercise of these securities were excluded in the computation of diluted net income per share as their effect would have been anti-dilutive. The number of outstanding weighted average anti-dilutive shares that were excluded from the computation of diluted net income per share consisted of the following (in thousands):