Why need Wildcard SSL Certificate?

[SSLMatrix]

The purpose of the Wildcard SSL certificate is to secure your main domain and sub domain over a single FQDN. Having Wildcard SSL certificate means you can deal with every sub domain and main domain on a server with digital signature. If you have many websites or many sub domains which all belongs to a single company, wildcard SSL certificate is right option for you.

All experts are well come to share your knowledge about wildcard ssl.

[Manov]

Yup!! I agree with you, all the features above you mentioned is available in Comodo Wildcard SSL
Certificate.

[alex11]

An SSL [Secure Socktes Layer] certificate secures the online transactions of a website. It safeguards the personal information of the user for safe online shopping. A WildCard SSL certificate is a step ahead. It not just enables you to secure the website but it also enables you to secure the sub-domains. This is done with the help of a single WildCard certificate. WildCard SSL certificate (https://www.rapidsslonline.com/wildcard-ssl-certificates.aspx) reduces the management time and cost to a great extent. The overall security is extended to all the sub-domains based on the top-level domain. For instance for a given website example.com, if an SSL certificate is used; only example.com will be secured whereas if a WildCard SSL Certificate is used on the website

*.example.com, it will secure -
www.example.com
mail.example.com
forums.example.com
blog.example.com and every other sub-domain linked to *.example.com.

If a WildCard SSL Certificate is used on the website *.www.example.com, it will secure -

mail.www.example.com
forums.www.example.com
blog.www.example.com and every other sub-domain linked to *.www.example.com.