Unfortunately, Gmail signatures does not gives us ability to use HTML in personalized signatures. So, basically you need to get the social media icons and paste it in the signature. Here are the steps and a video tutorial :
5 Simple Steps to be Followed
Step 1 Choose the social media icons you want in your email signature. Here are some of my favorite social networking icons in the form of skillfully hand-hewn and lovingly crafted package. (Hat tip Komodo Media).
Click on Edit using JS Bin on top right corner < Copy the URL of the desired social media icon which starts with http:// ends with a .png at the end (public link of icons). For example: http://therohanaurora.com/files/downloads/icon/facebook_16.png
Step 1 Upload your selected icons from above pack to a web-based file hosting service such as Dropbox, Picasa, SkyDrive etc. (How to use Dropbox ? [VIDEO]). Create public links on your own …
Step 2 Open your Gmail inbox < Settings < General < Select Use Signature
Step 3 Type your signature text < Click Insert Image < Paste the URL copied in Step 1 < Select the icon < Click on the globe to make it a hyperlink < Add your personalized URL where you want the user to redirect.
Step 4 Repeat this procedure in Steps 1 and 3 < Save Changes
Hope, things become more clear, when you watch this video.
This personalized signature may also bring plenty of traffic to your blog or Facebook fan page. If there are any ambiguities, don’t forget to leave a comment below.
I have also added the new Google Plus button in the above download packs. Make sure, you add the new social networking touch too.
Added Yelp, about.me and IMDB icons too.
Pinterest and Instagram icons added after so many requests. Anything else?