Photovine is set up similarly to Instagram, with a large button centered in the bottom menu for snapping a picture, which you can attach to a "vine" or create your own. A vine is a theme around which photos are grouped. Vines I saw included Nutella, Out a Plane's Window, Jordans, Breakfast of Champions, Green, and (of course) Kittens.
When viewing a vine, you can "like" a photo and add a comment. You can "watch" vines that interest you by tapping the Watch button in the upper-right corner, and they are then added to your Watching list. Two other lists of vines are labeled Fresh and Popular. Vines that you create or contribute to get added to your Watching list. You can also follow other users, which helps you keep tabs on their Photovine activity. You can find friends through Facebook, Twitter, your address book, or searching by Photovine user name.
When you are browsing a vine and tap the center button in the bottom menu, the camera app opens and the picture you snap will then get added to that vine. You can then add a 40-character caption and choose to share on Facebook or Twitter, currently your only social-networking options. (Why Google launched Photovine without Google+ integration is a mystery to me.) You can also "loop in your friends." Looped-in friends will receive a message in their Photovine inbox about your recent post. Tap the Post button in the upper-right corner and your photo gets added to the vine.
If you are not viewing a particular vine when you snap a photo, you can then create your own vine. As you type out a title, existing vines appear to avoid duplication. To flip through the photos in a vine, you can use the arrow buttons below the images or just swipe sideways.
In addition to the photo button on the bottom menu, you'll find buttons labeled Activity, Vines, Inbox, and Profile. The Activity page simply lists the photos you've added to vines. The Vines page lists various vines, under the Fresh, Popular, and Watching headers. You inbox includes notifications and messages; you'll get a notification when someone chooses to follow you or loops you when they post a photo, and messages are simply text messages sent from user to user. Lastly, from your Profile page, you can see your followers, those you are following, the photos you've liked, and thumbnails of your posts. You can also upload an image for your profile picture, which by default is a monkey because, I suppose, monkeys like climbing on vines.
The design is very un-Google like, with no mention of Google in the branding and a light-green-and-brown color scheme. There are also no filters, which I would consider the biggest omission of Photovine. Photo filters are what make apps like Instagram and Hipstamatic so creative and fun.
So, that's Photovine in a nutshell. Do you think you'll try it in addition to or in place of Instagram or Hipstamatic? Please share your photo-sharing habits in the comments below.