6. Goodwill and Intangible Assets

Goodwill and indefinite-lived intangible assets are not amortized but are reviewed annually for impairment or more frequently if impairment indicators arise. The Company did not have any intangible assets with indefinite lives other than goodwill as of March 31, 2024 or December 31, 2023. There were no indications of impairment as of March 31, 2024, and the Company believes that, as of the balance sheet dates presented, none of the Company’s goodwill or intangible assets were impaired.

Intangible assets are amortized over their estimated useful lives, which range from eighteen months to nineteen years, using methods of amortization that are expected to reflect the estimated pattern of economic use. The remaining amortization expense will be recognized over a weighted-average period of approximately 6.3 years. Amortization expense was $2.2 million both the three months ended March 31, 2024 and 2023, respectively. Amortization expense relating to developed websites, technology and patents is recorded within costs of revenues. All other amortization is recorded within operating expenses as the remaining intangible assets consist of customer-related assets which generate website traffic that the Company considers to be in support of selling and marketing activities. The Company did not write off any fully amortized intangible assets in the first three months of 2024 or 2023.