Dear Internet: please move the share buttons from the web page to the browser
The mobile browsers have already shown the way - a single share button, share with any service (yes, there needs to be some open bring-your-own-service functionality like we already do for search).
I'm hoping one or two people who are working on one of the major browsers would read this and "simply put it in" and we'd eventually all be living with a cleaner, faster loading web as the on-page buttons go the way of the dodo.
Not to mention that it would actually be really useful.