Nk
Defunct2 known investors
NK.pl (formerly Nasza-klasa.pl) was a Polish school-based social network, launched in 2006 and shut down in July 2021.
Also known as Nasza Klasa · Nasza-klasa.pl · NK.pl
Investors · 2
Company profile
researched Aug 2026NK.pl, originally Nasza-klasa.pl ("Our Class"), was a Polish school-based social networking service for students and alumni. Registered users selected their school and graduation year, built personal profiles describing their lives and past education, and used the site to reconnect with former classmates and share photos, posts and messages. The service required registration and offered a range of privacy settings together with guidance on privacy, operated a trust and safety function that cooperated with law enforcement on threatening or illegal content, and cooperated with child-protection organisations including the Nobody's Children Foundation.
The site was headquartered in Wroclaw, Poland, and its name derived from the Jacek Kaczmarski song "Nasza Klasa". At its peak in 2009 it ranked among the top five websites used in Poland, behind Google.pl, Onet.pl and Wirtualna Polska, and was visited by more than half of Polish internet users each month, with about 10 percent of traffic originating abroad; it was also the fifth most popular social networking site in Norway in 2009. A 2009 academic study described it as a model example of an enterprise built without financial funding or institutional support. The service was ultimately owned and administered by Ringier Axel Springer Polska and ceased operating on 27 July 2021.
Founding story
The site was launched on 11 November 2006 by Maciej Popowicz, Pawel Olchawa, Michal Bartoszkiewicz and Lukasz Adzinski, four computer science students at the University of Wroclaw. The name came from the Jacek Kaczmarski song "Nasza Klasa". A 2009 study cited its development as an example of an enterprise built with no financial funding and no institutional support from ISP corporations or from central or local administration. After selling his stake, Popowicz co-founded the mobile games company Ten Square Games with Arkadiusz Pernal.
Business model
The service was free to register and operated as a mass-audience consumer web portal monetised through advertising and portal traffic; after the 2014 acquisition by Ringier Axel Springer Polska the owner shifted the property away from social networking toward online games. Following the 2021 shutdown the nk.pl domain serves as a directory pointing visitors to the owner's other online game platforms, GamePlanet.onet.pl and Onlygames, and to Onet and Fakt editorial content.
Registration was free and the service was operated as an advertising-supported consumer portal; the June 2010 terms-of-use change sought user consent for commercial use of profile photographs and selected private information. Under later ownership the site shifted toward online games.
Traction
The service reported 13.5 million active users in 2009 and about 12 million monthly visitors during its 2008-2011 peak, when it was visited by more than 50 percent of Polish internet users each month. Registered users fell to fewer than 7 million by August 2014 before the service closed in July 2021.
Latest developments
The portal was shut down on 27 July 2021 and the nk.pl address now displays a closure notice alongside a catalogue of online games and links to Onet and Fakt content. In September 2025, Polish press reports about a revival of Nasza Klasa were assessed as inaccurate: the application at naszaklasa.app is a separate, template-based mobile product offering school and classmate search, photo and video posting, chat, groups and a paid "NK Premium" tier at PLN 19.99 per month, published by ourCLASS and AppVentures, which state the project is not affiliated with, sponsored by or authorised by the former nk.pl portal and that trademark protection for the "Nasza Klasa" and "nk" marks had lapsed. Accounts and content from the former portal were closed at shutdown and cannot be recovered.
▸Full profile — market position, go-to-market, geography, history, risks & controversies
Market position
In 2009 NK.pl was among the five most-used websites in Poland, behind Google.pl, Onet.pl and Wirtualna Polska, and between 2008 and 2011 it was the country's most popular social networking service. Its position eroded as Facebook expanded in the Polish market, with registered users falling below 7 million by August 2014, and the repositioning toward online games under Ringier Axel Springer Polska did not restore performance, leading the owner to concentrate on its GamePlanet.onet.pl and Onlygames platforms.
The service was organised around schools and graduation years rather than open social graphs, letting users locate former classmates and teachers by institution and year, and it emphasised privacy settings and cooperation with law enforcement and child-protection bodies. Contemporary Polish commentary characterised it as the first domestic social portal to achieve mass scale, and described it as a milestone in the development of the Polish internet that brought ordinary users, rather than only specialists and young people, into online life.
Go-to-market
Polish school students, alumni and teachers seeking to find and stay in contact with former classmates, later broadened to a general consumer audience including millennial and early Gen Z users attracted by free online games.
Geography
The company was headquartered in Wroclaw, Poland, and its audience was overwhelmingly Polish: as of July 2009, 86 percent of users lived in Poland according to Alexa, with roughly 10 percent of traffic coming from abroad. The service also had a following in Norway, where it was reported as the fifth most popular social networking site in 2009.
History
Launched on 11 November 2006 as nasza-klasa.pl, the site grew rapidly to become Poland's leading social network, reported at 13.5 million active users in 2009 and roughly 12 million monthly visitors between 2008 and 2011. Ownership changed repeatedly: founder Maciej Popowicz sold a 20 percent stake to the European Founders fund in 2007 and a majority package to the Latvian company Forticom in 2008 for close to PLN 200 million; the vehicle Excolimp later held 73 percent and, in November 2014, agreed to sell the service to Ringier Axel Springer Polska. A June 2010 rebranding to NK.pl and changes to the terms of use covering commercial use of profile photos and selected private data coincided with a heavy loss of users, and by August 2014 registered users had fallen below 7 million as the audience moved to Facebook. The new owner repositioned the portal around online games rather than social features. Closure was announced on 26 May 2021 and the service was switched off on 27 July 2021, after almost 15 years. In September 2025 press reports of a "return" of Nasza Klasa referred to a separate mobile application at naszaklasa.app, which its operators state is an independent project by the companies ourCLASS and AppVentures, unaffiliated with the former nk.pl portal.
Risks & controversies
The June 2010 rebranding and revised terms of use, which required users to allow the portal to use their profile photographs commercially along with selected private information, were followed by a mass departure of users. Competition from Facebook drove a sustained decline in registered users, from a 2009 peak of 13.5 million active users to under 7 million registered users by August 2014, and the pivot to online games under Ringier Axel Springer Polska performed only moderately, contributing to the 2021 shutdown amid the owner's cost reductions after revenue declines. Separately, an unaffiliated mobile application launched at naszaklasa.app uses similar naming and colours, which Polish press coverage flagged as potentially confusing for former users.
Compiled by commissioned research from 8 cited public sources — announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed — not independently audited.
Timeline · 7
launches, deals, and filingsThe service was dissolved on 27 July 2021 after almost 15 years of operation; the domain now shows a shutdown notice and links to online games.
NK.pl announced it would shut down on 27 July 2021; new profile registrations were stopped and users were given about two months to download their photos and other content. The owner said it would focus on its GamePlanet.onet.pl and Onlygames platforms.
Ringier Axel Springer Polska signed an agreement to acquire NK.pl from Excolimp Investments, which held 73 percent of the service.
A June 2010 rebranding and changes to the terms of use, requiring users to permit commercial use of profile photos and selected private information, were followed by a large loss of users.
Latvian company Forticom acquired a majority stake in the service for close to PLN 200 million.
A year after founding, Maciej Popowicz sold a 20 percent stake in the platform to the European Founders fund.
The school-based social networking service was launched by four University of Wroclaw computer science students: Maciej Popowicz, Pawel Olchawa, Michal Bartoszkiewicz and Lukasz Adzinski.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
▸Research sources · 8
primary sources listed
- Nknk.pl · web
8 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Nk do?
- NK.pl (formerly Nasza-klasa.pl) was a Polish school-based social network, launched in 2006 and shut down in July 2021.
- Who are Nk's investors?
- Nk's investors include RubyLight, Trind Ventures.