I hope it's the right place for asking help. Well, I am promoting my twitter account and just wondering what's the right URL to promote. Should I use the url staring with http or go with the url staring with www . what are the differences between urls starting with http and www? Advantages and disadvantages? Pro and cons? also welcome. Thanks..
Twitter is using the non-www version, www version had been redirected to the non-www. Therefor i suggess using the non-www version for promoting your twitter account. That redirect may take a bit more time and it's better to go to the direct URL version of the website when you promote.
In general, you want to link directly to the www or http, whichever one the URL happens to be (in twitter's case, the non-www version). If you are setting up a site, it's probably best to eliminate the www. since it's kind of pointless and a waste of characters. But at the same time, it isn't vital so if you already have www. in your site, I wouldn't fret.
Using the full address (using http) is a good idea to go with and another benefit is in most cases this type of urls convert into hyperlinks automatically (e.g. when you refer a url in comments)
search engine wise it makes no difference. For users benefit use the "http:// xxx.com" format. Simply easier to remember.