I am developing a website providing some techincal knowledge, and my major concern is whether to host this site on a free hosting service, or can I use the Salesforce's free DEV org? What all are the things to consider before taking a decision?
The "free" hosting provided by salesforce.com is rather limited, as illustrated in the Force.com Sites Limits and Billing page. Notably, you only get 10 minutes of processor time in a Developer Edition account (compared to 60 hours for a production environment), and only 500 MiB of bandwidth (compared to 40 GiB for a production environment).
The processor limit is probably going to be your ultimate limiter, as you'll probably only be able to get a maximum of 6,000 page hits per day, based on those time limits, and much less if your pages are considerably "heavy" in terms of CPU time. Most free hosting sites are more generous than these paltry limits; even a single dyno on Heroku provides better processing power than the limits you'd experience in a Developer Edition. On the other hand, if you don't think you need more than 10 minutes per 24 hours in processing time, that might be enough.