I think you are already known with many short URL generator websites but out of them bit.ly is my favorite (due to its tracking features). Today while working on Bit.ly, i noticed that it is declaring all the urls of tinyurl as flagged and unsolicited.
I noticed few results on Bit.ly which are listed as follows
1. First i test for the tinyurl where i short the http://www.google.com/webmasters/index2.html into http://tinyurl.com/y8swgbx. When i again try to short the tinyurl through bit.ly it reflects the warning messages.
Warning – this site has been flagged and may contain unsolicited content.
Latter i thought there might be any issues between bit.ly and tinyurl so i should check with another url shorter service.
2. I pick up is.gd and short the url http://www.google.com/webmasters/index2.html to http://is.gd/4vFvv. When i again try to short http://is.gd/4vFvv into http://bit.ly/4rnuPk, it reflects the same warning messages.
4. http://bit.ly/2tgXDe with source http://u.nu/9ctm3 also reflects the warnings
5. http://bit.ly/RBwmz with source http://tr.im/CEkY also reflects the warnings
6. After searching for other url shorter service i found re-url.me. I again short the http://www.google.com/webmasters/index2.html into http://re-url.me/2755 and that into http://bit.ly/2DBHO7.
Observation: This time http://bit.ly/2DBHO7 doesn’t reflect any warning and successfully redirect to http://www.google.com/webmasters/index2.html
Question: Why Bit.ly ban the redirects to other url shorter services ? Is it due to competitions or to really avoid the phishing? If we ask this question to bit.ly then they will sure say that “It is hard to track every urls so its better to auto scrap the urls having questionable re-directions”