The USP of Sysinclude is that it is open to Indian IT pros only, that too from within a selected 125 Indian IT companies.
So you can register on the site only if you belong to one of
the 125 Indian IT companies their system recognizes (you’d need the corporate
email ID for registration) much like what Facebook had for educational
institutions initially.
The only danger, I foresee is once the site takes off; there is no guarantee that they will stay reclusive. They may even open up like Facebook.
Personally, I would not like to give away my corporate email ID, as recruiters are sure to take advantage of it.