We have a Facebook page. The link is in my sig. We made it early on, probably too early. I use Facebook and Twitter for reminding people when the comic is updated, new fan art, things like that. I just post the link and it shows up in people's feed. I love it because we get a lot of traffic from those sites. Which means people forget we update on Thursdays or they just like the convenience of clicking on a link from their feed which they are always checking.
Battle Creek, NE - The Webcomic Official Facebook Page
I've found having a Facebook page really helps with readership and keeping people coming back every week cuz not only can you remind them when it updates but post art and related stuff in between and it keeps people interested.
Location:a land of chocolate milk and honey nut cheerios
I've got one for Too Strange for Words. It was started primarily because Erika and I have real life friends that don't subscribe on comicfury. And instead of spamming everybody's feed with our updates, we just made a page for our friends that were interested. Other stuff happens there too.
I tried doing FB for my comics, but the religious and relative trolling became unbearable. It is my understanding that FB is not the best place for anything too controversial. Google+ makes me much happier.