Etiquette with facebook messages from strangers?

[rimidis]

I post thoughts in a facebook motivational forum and some people (mostly men) contact me with friend requests or just messages saying a "hi" or "how are you". I am really not sure how to respond when am not feeling too inclined towards getting to know them. Should I just ignore? Though that sounds rude, to continue to post but never respond to them, who see your posts. I don't want to create bitter feelings. Or should I respond anyway out of politeness - though I don't want them to be encouraged by this. What would you do? Thank you.
Sue, it's a regular facebook page of a speaker/organization with a purpose.