I recently have been asked what I thought about share buttons these days.
While I recommend adding share buttons on blog posts, when I see clients adding them I often find something wrong.
10 reasons why you shouldn't add Social Share buttons:
The first big concern is speed: those widget normally download additional CSS files and - most importantly - script files; they do not always use async scripts and tend to slow down page load time dramatically.
The worst cases are when the widget are added in the blog roll, but developers messed up and included a script for each instance of the share button.
Don't you love when you do your best to be fast, and someone pulls the break?
No, not this kind of cookies
Note: setting cookies is not normally needed per-se to share a link, share platform often also act as tracking systems and need to set cookies to accomplish it.
Developers when asked to add social media share buttons often add them using some widget that permits sharing links on so many social media channels they never even heard about.
Some are not really strategic in my opinion for the customer audience. I'd prefer only share buttons for channels where the client has an online presence. As a general rule of thumb, no more than three buttons, please.
I bet they are using more than they can manage
One thing I don't really like is when share buttons are shown in the users' face straight away before they could even read the article.
It's controversial, and I've been on the losing side several times when discussing it with clients.
To me it's like trying to date a woman asking her to bed you before even introducing (pun not intended) yourself.
Don't be too pushy if you want to achieve
You might succeed in some occasions, but you probably have better chances making acquaintance first, making her laugh, let her know you better and build a relationship.
I hate when social media buttons overlay the text I'm supposed to read. This often happen if I use the browser zoom functionality or when using a mobile device, but I experience it also in normal desktop conditions, on the most widespread desktop browser.
Didn't they bother to test it?
Of course such an awful user experience is an almost certain guarantee of a bounce: I usually give up straight away reading the article and hit the browser back button in no time.
Note: I'm too lazy right now to find an example where to get an explanatory screenshot, but someone did a very good job describing the issue: Think Again: is your social media share bar helping or hurting?
For website where everything should be tuned toward driving the user to convert (e.g. leaving your data, downloading a file, ...), social share buttons are a secondary call to action distracting the user.
Your site Call To Action, your User, and Everything Else
Social media button are an element of distraction. Especially when shown upfront they pose a threat to the already short reader attention span.
A webmaster should take this into account before adopting them, and measure possible changes in conversion rate to balance costs and benefits.
Using non-customized social media button plugins is adding a bunch of variously colored boxes which is like a poke in the users' eye. You spent so much time paying a web designer for your website unique style, and then ruined it all.
Share buttons can be like a poke in the eye
Social media share buttons should be used - if ever - only where they make sense: no one will ever share your ToS page, your cart page, pricing page, product page...
Users do not share your content to advertise your company/product/brand, they share your content because they appear cooler sharing interesting content. Keep that in mind.
So stop adding them in every single page, they will only confuse users and slow down your site. Probably the only place where it makes sense adding them is at the bottom of a blog post.
Google+ has vanished since months, why do webmasters still keep it in their social share buttons?
A Google+ share button, well after G+ was dismissed
And yet another thing: the best social media buttons - if you ever need them - are custom made share buttons, carefully crafted to ensure a look and feel consistent with your website design, minimize the performance overhead and not setting third party cookies.
Do not settle for that plugin just because it was the first thing you come across!
A nice comparison of social media share buttons solutions I stumbled upon is A Big Test of Social Media Buttons – Performance, Privacy, Features
While not too recent, it takes into account both performance, privacy, an ability to blend with your site look and feel.
Another resource worth reading is Saying no to social media buttons, which discuss the usage of social media buttons in general, not only share buttons.
Again, I normally do recommend adding share buttons to your blog posts, and sometimes somewhere else where it makes good sense: for example at the end of a purchase process it might be a good idea to permit the happy user to tweet about his new cool gadget.
What I wanted to point out is that often social share buttons are added where they add no value; their implementation is often a performance nightmare; their impact on the overall design disturbing; they are annoying, they tend to backfire going against the website goals, etc...
To cut it short: they should be added with a grain of salt!
Did I miss some point worth mentioning?