Why do social networking websites need venture capital?

[Simeon]

I know facebook received approximately $150,000,000 of venture capital and Twitter received $20,000,000 to run expensive servers/marketing, however is there any other reason as to why a website would need this kinda of finance?

[angelacatirina]

All businesses, even not-for-profit organizations like charities, need operating cash to survive. The money is used for marketing, research, employee salaries, rent, insurance, expenses, professional fees like attorneys & accountants, etc....