Social Media
Social media includes web- and mobile-based technologies which
are used to turn communication into interactive dialogue among
organizations, communities, and individuals.
Social Networking Service
A social networking service is an online service, platform, or site that focuses on facilitating the building of social networks or social relations
among people who, for example, share interests, activities,
backgrounds, or real-life connections. A social network service consists
of a representation of each user (often a profile), his/her social
links, and a variety of additional services. An example would be Mark Zuckerberg's Facebook which was launch in February 2004.
Software licenses
A license defines the way you can legally use the software you buy or the software you find on the web.
Proprietary Software
You have permission to use the software under the vendor's conditions. This usually means you cannot make copies of the software, you cannot distribute the software and you cannot change the software. The vendor may give you a limit of number of computers in which the software can be installed.
Shareware and Freeware
The software is available for free on the web under different conditions.Sometimes you have a "trial period" before you have to pay a fee to use it, sometimes you have to pay to use all the features, sometimes you agree to see advertising displayed on your computer in exchange for using the software, etc. You cannot modify this software.
Free/Open Source Software
You can use, change and distribute the software for any purpose. There are different licenses, but in general they allow you to access the software and re-distribute it freely.