There are Facebook share button and Twitter share buttons, is there one such button for Google+? The +1 button doesn't seem to be a Google+ share button, it just seems to be a social search recommendation.
The +1 button is now (or soon) set to allow for sharing on Google+.
Here's a quote from SilconFilter:
Starting today [August 24], though, the +1 button will finally become useful. Over the next few days, Google will roll out an updated version of the button that will allow users to use it to share content with their circles on Google+. The button will also automatically add text snippets and images from any page you want to share, similar to the feature Google introduced on Google Books earlier this month.
I'm in the preview program, so my account is already rolled out. I just used it and it works as advertised.
Google +1 is equivalent to the Facebook and Twitter share buttons. When you click +1 on a post, it's the same thing as when you share a link through the other web services.
The thing you have to note is that it won't show if you're using the +1 from inside a post on a Google+ Circle. It will show if you click it from a website or Google search. That's the public/private distinction.
Use the +1 button to publicly show what you like, agree with, or recommend on the web. The +1 button can appear in a variety of places, both on Google and on sites across the web
When you're logged into Google+ you'll see a tab labelled +1's. This collects those pages and such around the Internet where you've clicked that +1 button on.
You can share this tab with the public and its contents.
To change your tab settings to allow public viewing of your +1 items:
- Sign in to Google+
- Click the Profile icon at the top of the page
- Click Edit profile
- Click the tab you'd like to edit
- Choose the appropriate tab visibility setting
- Click Save.
The +1 button is not actually for sharing stuff on Google+. It is just like Facebook's 'Like' button but not the 'Share' button. The +1 button adds a sort of recommendation from you as a user, which helps in Google Search by showing up higher in search results especially when you and your friends are logged in to Google. I basically suggest that your friend has +1d it, so the search result may be relevant for you as well.
I found code for a Google+ Share button here: http://www.stateofsearch.com/share-on-google-plus-any-website/