Well I myself surely failed to notice that they were down. Both sites have been working just fine for me.
Technical glitches do happen. I've experienced my internet connection being down for two days. Same with my TV channels at another time - nothing but "weak signal" and no picture and/or sound on every channel. Just a few days ago half of my TV channels were down.
Gmail not working for some time? Facebook not working for some time? Twitter not working for some time? Is it really a big deal if they don't work all the time?
Gmail started in 2004. Yet people send e-mail to each other happily even before that.
Facebook was launched as a restricted service in 2004 (not everyone could just join in), and it became generally available in 2006. Twitter also started just in 2006. Yet people were happily communicating with each other long before anybody had even heard about these particular sites.