Neil Patel on pronetadvertising.com talks about how too many social bookmarking icons will confuse and distract your readers.

I guess the question is, why shouldn’t you be giving tons of options to your website visitors? It may seem like a good idea at first, but your ever so curious visitors will end up clicking on random buttons which will take them to sites that they are not familiar with and then they will not bookmark your content. Even your most tech savvy readers don’t have accounts at most of these social sites, so why drive them to sites where they will not bookmark your content.

The blog post is really basic common sense. So if you feel you have too many icons go read it! But, before that I would just like to add one thing. If you use the AddThis bookmark and feed buttons your readers and visitors can easily choose which social bookmark site they want to use. They just need to choose the “Please don’t ask me every time” option.