In order to deliver the data streams to a client, a server needs to use the mechanism called datafeed. The data transfer can be done automatically or according to the clients wishes. The most important thing about the data factor is the file format. It has to be predefined and in compliance with the client application standards so that it would be actually useful to the user. Web feed is the most common form of datafeed. It carries the information that regards real-time web-based applications. The rich site summary (RSS) feed is a common variant of web feed. It allows blogs and other kinds of websites to supply their subscribers with news excerpts automatically.