site/_includes/social_links.html
<div class="social-icons">
<div class="center">
{% if site.github_username %}
<a class="fa fa-github" href="https://github.com/{{ site.github_username }}"></a>
{% endif %}
{% if site.stackoverflow_id %}
<a class="fa fa-stack-overflow" href="https://stackoverflow.com/users/{{ site.stackoverflow_id }}"></a>
{% endif %}
<a class="fa fa-rss" href="{{ "/feed.xml" | prepend: site.baseurl }}"></a>
{% if site.twitter_username %}
<a class="fa fa-twitter" href="https://twitter.com/{{ site.twitter_username }}"></a>
{% endif %}
{% if site.google_plus_id %}
<a class="fa fa-google-plus" href="https://plus.google.com/{{ site.google_plus_id }}/posts"></a>
{% endif %}
{% if site.email %}
<a class="fa fa-envelope" href="mailto:{{ site.email }}"></a>
{% endif %}
{% if site.linkedin_username %}
<a class="fa fa-linkedin" href="https://www.linkedin.com/in/{{ site.linkedin_username }}"></a>
{% endif %}
{% if site.angellist_username %}
<a class="fa fa-angellist" href="https://angel.co/{{ site.angellist_username }}"></a>
{% endif %}
</div>
<div class="right">
{% if site.bitcoin_url %}
<a class="fa fa-bitcoin" href="{{ site.bitcoin_url }}"></a>
{% endif %}
{% if site.paypal_url %}
<a class="fa fa-paypal" href="{{ site.paypal_url }}"></a>
{% endif %}
{% if site.flattr_button %}
{{ site.flattr_button }}
{% endif %}
</div>
</div>
<div class="clearfix"></div>