The primary difference is the way in which the content is delivered. While Internet TV travels over the globe, IPTV uses a personal and managed network.
In other words, IPTV may be a technology that permits television services to be delivered over a proprietary broadband packet data network using the web protocol suite. While IPTV and Internet TV on the other hand may be a television broadcast service distributed over the web.
IPTV is the multicasting of content within a managed network while Internet TV is only broadcasting on an un-managed internet-based network.
As the name suggests Internet TV leverages the general public Internet to deliver video content to finish users. Moreover, IPTV always used secure dedicated private networks to deliver video content to consumers. All of these private networks are always managed, operated, and dimensioned by the service provider.
IPTV delivery may be a higher quality, more reliable, and more consistent viewing experience while Best-effort Internet videos are often subject to delays thanks to lower bandwidth, high traffic, or poor connection quality.
A digital set-top box is usually wont to access and decode the video content delivered via an IPTV system whereas a PC is almost always wont to access Internet TV services.
Since the internet is more flexible and open than a propriety network, the dedicated home computer may also require digital rights management certification in order to ensure compliance with copyright laws. In the IPTV service case, copyright laws are handled during the contract negotiations between the operator and therefore the media company providing the fabric (films, TV shows, etc).
A big percentage of video content delivered over the general public Internet is out there to consumers freed from charge. IPTV services on the other hand are provided for a fee which might be a monthly subscription and which could include other bundled offerings.
In the past, an honest share of Internet TV video content was user-generated. Today user-generated content falls under the term of Web TV while Internet TV is analogous to a classical broadcast service but through the web. On the other hand, IPTV has always distributed traditional television shows and films supplied by established media companies.
I hope this article will give you a basic idea about the differences between IPTV and Internet TV. If further info is required, feel free to ask in the comment section.