When you have a link from lets say twitter that is
t.co/foo that links back to your website how does that effect SEO and how do the major search engines handle Shortened URLs?
Here is an answer from Matt Cutts at Google.
As Chris said, if 301s are in place then everything will be fine.
This will depend on the redirect the service you are using employs. If they are using a 301 permanent redirect, then all the link juice should be passed to your site just fine. There are a few common place services that use 302 temporary redirects but search engines treat them the same as 301s due to the profile of the service.
It depends on the implementation of the URL shortener in question. If implemented in an SEO friendly way, then using a URL shortener will not hurt your SEO efforts compared to direct linking. For a URL shortener to be SEO friendly, it should:
- Use 301 permanent redirects not
- 302 temporary redirects
- meta refresh
- Allow crawlers to access it
- Allow crawling with robots.txt
- Don't include x-robots headers that limit crawling or indexing
- Show the same redirect to users and search robots
- Be stable and robust -- consistent results with little downtime
Not all URL shorteners are SEO friendly. You should check the above items for the one that you are using.
Source: duplicate question