The Public Interest Network (PIN) is a collection of over one hundred left-wing nonprofit and for-profit organizations headed by Doug Phelps, a powerful Democratic Party political operative connected with the Democracy Alliance network of left-of-center donors. The network consists of the U.S. Public Interest Research Group (USPIRG), many state-level PIRGs, environmentalist group Environment America and its state-level chapters, and many other nonprofit advocacy groups. The network of groups has been dubbed “the Liberal Sweatshop” for its labor practices. 
PIN is notable for its use of paid canvassers supporting left-leaning client organizations across the country through its 501(c)(3) nonprofit clearinghouse, the Fund for the Public Interest, which works in alignment with allied left-of-center campaigns.
PIN has been criticized by former employees for being a hostile working environment. 
For information on the creation of the PIRG model, see Donald Ross
The Public Interest Network is the umbrella organization that contains over one hundred nonprofit and for-profit groups, including the United States Public Interest Research Group (US-PIRG) as well as its state affiliates and Environment America and its state affiliates.
The Network grew out of the public interest research group (PIRG) model developed in the 1970s by community organizers Ralph Nader and Donald Ross, who worked as executive director of the New York Public Interest Research Group (NYPIRG) from 1973 to 1982. Ross and Nader detailed the PIRG model in their 1971 book Action for a Change.
The Public Interest Network consists of many different organizations, many of which share staff. The network claims that it has over 400 staff members across 114 organizations. Various state Public Interest Research Groups, U.S. PIRG, state Environmental America affiliates in 29 states, Environment America, Environmental Action, Center for Public Interest Research, Toxics Action Center, Pesticide Watch, Green Century Capital Management, Green Corps, National Environmental Law Center, Frontier Group, Community Voters Project, Snowriders International, Accelerate Change, Impact, and Bold Alliance are among the members of the network. 
Public Interest Network member Grassroots Campaigns, Inc. (GCI), a for-profit consultancy led by PIN officers including Doug Phelps, contracts with the Human Rights Campaign (HRC) to conduct HRC’s canvassing operation. Former employees of GCI have asked HRC to break ties with PIN due to exploitative employment practices. A protest website aimed toward the Human Rights Campaign claims PIN provided canvassers with very low pay, overworked its employees, and did not act on reported abuse and harassment. 
An anonymous critic created a website alleging a toxic working environment at PIN, stating: 
The underlying principle of staff management at [PIN] is that employees are disposable. This is not an exaggeration—the expectation is that you will quit. This is most clearly visible at the Fund [for the Public Interest], where the average canvasser lasts two weeks and canvass offices have to hire staff all summer long. The turnover rate is at least 500%. But this revolving door is attached to every entry-level position in the Network. [PIN] is intentionally constructed to—on a perpetual basis—hire idealistic recent grads, indoctrinate them with the Model as much as possible, overwork and underpay them until they quit, and repeat.
Liberals have criticized Phelps and PIN for opposing proposed changes by the Obama administration that would have raised the salary threshold for an exemption from time-and-a-half-pay overtime rules. U.S. PIRG, a PIN member organization, stated that it “will be forced to hire fewer staff and limit the hours those staff can work” if the rule went into effect. 
For more information, see Doug Phelps
Doug Phelps leads the Public Interest Network. Phelps is a left-wing activist who has been active decades and has many titles connected with his network. Phelps also controls a personal grantmaking foundation, the Douglas H. Phelps Foundation.