Marketing
I think people don't use alternatives because they don't know about them. A great example is how many "social networks" do you know of?
A recent survey has shown over 500 "popular social networks" exist (sorry I cannot find the link to the resource now but do a quick search and you will find websites that list hundreds regardless), so have you joined "Avitars United" or "Cloob"? Did you even know these websites exist? I only found them now on Wikipedia in a list of "social networks".
The best way to move people to better services is to tell them, invite them to use the service and encourage them. Marketing is bloody hard and the likelihood that my company with a better solution than what is being used can reach you is pretty minimal, even with massive marketing budgets then will you get my message? I doubt it.
So do your part to spread the word of great services you find. Don't be embarrassed to recommend but do make sure you're recommending something that is likely to be valuable to the person you're recommending it to. For example I would not recommend TechRepublic to my mother who is in her mid 50s and only got the nerve to turn the computer on a couple of years ago but I would recommend it to my dad who has always been and early adapter to technology and does some work for technical companies as an accountant.
