I use a side blog on tumblr dedicated to my comic, after followers kept leaving my main blog every time I posted a new page. I also post pages on deviantART but I'm really considering deleting that now, so little interest on there, only really keep it for the favourites.
I only joined Tapastic a couple of months ago, but the support and love of the community is unlike anything I've felt elsewhere.
I think the general feeling amongst creators is that if you can afford to, you should make your own website as it's more flexible and professional. But I'm happiest here! 