What is the perfect definition of tiny url?

is tiny URL is search engine friendly ? and trust able?

No and no. =p

First the easy one: trustworthy. Answer: not really. We had a great discussion about this topic a while back here: http://www.sitepoint.com/forums/showthread.php?796739-URL-shorteners-still-needed

The second, is it search engine friendly. Answer: I’ll let you answer that one.

Which do you think tells the search engine more about your site:
http://www.bayareaplumber.com/commercial-water-repair

or

http://tiny.co/ab3yX

=)

(Also, as a note, that URL pointed to some dummy landing page when I posted this =p)

Tiny URL is great for minimizing and sharing extremely long and cumbersome urls, such as an item on a particular online store or an article that’s buried deep inside a website. However, I’d stay away from using tinyurl for SEO purposes. Your better off linking to the full page URL.