If you are going to use an URL shortening service, please go with one that is universally recognised by most tech people, such as bit.ly. I've never heard of tweak.tk and I've never seen it come across my Twitter feed.
The cool thing about tweak.tk is that it's operated by the .tk-registry and you're getting a free generated .tk domain instead of just a page on the domain of the shortening service. Jdyk56.tk instead of bitly.com/jdyk56