While Google has condemned buying and selling links that pass PageRank, they've encouraged listing in paid directories like Yahoo for years. It seems that era may have come to an end earlier today. The following bullet points have been removed from Google's Webmaster Guidelines Webmaster Help Center*
"Have other relevant sites link to yours."
"Submit your site to relevant directories such as the Open Directory Project and Yahoo!, as well as to other industry-specific expert sites."
Does this recent move reflect a renewed emphasis on rooting out paid links passing PageRank and/or low quality links by Google?
*As mentioned, the bullet points above have been removed from the US version of Google's Webmaster Help Center. Other versions may not yet reflect this change.
A friend of mine recently emailed to ask, how TinyURL impacts SEO? It's a good question and one many folks can't answer so, I thought I'd blog my answer to his question!
For anyone not familiar with TinyURL, in layman terms it's a tool where users can enter long displaying URLs to get a shortened version. TinyURLs are often used where long URLs might wrap and therefore break, such as in email or social media web applications like Twitter. In more technical terms, TinyURLs are short, dynamically created URLs that redirect users to another intended URL via 301 redirect. Because TinyURLs "301" or permanently redirect, search engines should not index the TinyURL but instead should index and pass PageRank to the actual URL.
It is important to note, TinyURLs to paid links passing PageRank is a violation of Google Webmaster Guidelines and that sites like Twitter use nofollow techniques to prevent spam.
On their own, TinyURLs can be search engine friendly from a technical perspective. At the same time, I wouldn't suggest replacing your site's navigation with TinyURLs and would point out that tracking TinyURLs via analytics might be difficult.