'com' is one of the top-level domain name that can be used when choosing a domain name. A domain name is an identification label that defines a realm of administrative autonomy, authority, or control on the Internet, based on the Domain Name System (DNS).
'com' generally describes the entity owning the domain name as a commercial organization. 'Italki' could have been labeled 'edu' ( www.italki.edu) as an educational site,but 'edu' domain registration is for the most part limited to schools located in the United States.
Other top domain names :
edu , gov , net , int , org ...