DOT TK

.tk is the Internet country code top-level domain (ccTLD) for Tokelau, a territory of New Zealand located in the South Pacific.

Tokelau provides any interested individuals .tk domain names free of charge, and you pick if you want advertising banners on all provided domains. These free domains are pointed to Tokelau nameservers, which redirect HTTP traffic via HTML frames to a specified web page. The domains also redirect 250 email addresses to external addresses. Because of this redirection, use of free .tk domains for other services (such as hosting servers for other protocols such as FTP and IRC or creating hostnames and subdomains within them) is not officially possible. Sites not visited at least 25 times in consecutive 90 day periods are automatically cancelled to avoid the domains being unavailable to more active websites.
Dot-TK recently provided .tk websites the option to join a network called TiKinet, a close-knit network that links sites to each other based on key words called TiKilinks. The network is expected to increase traffic to the websites, many of which are personal sites and blogs operated by individuals who otherwise would have no way to advertise their sites. To be able to use one's own nameservers, or get a "special" .tk domain name, for example, trademark domain names for most Fortune 500 companies, and to avoid advertisements, the user must buy it. Paid domain names start at $19.90 US for the first 2 years.
Potentially valuable names with less than 4 characters are unavailable for free registration, and must be purchased - usually at a premium price of over $1000 USD.