Plz help me am doin a dissertation on marketing and internet technology how it has changed marketin in these new market.

I think you already have a topic i.e.

"The Role & Value of Internet Technology in Modern Marketing – A Review of Perspectives & Prospects for the Future"

You can research the variety of opinions "for" and "against" the role and value of internet technology in marketing and build your dissertation around these perspectives or ‘themes’, in what I call a "thematic dissertation".

Good luck.