For a long time now I’ve run a Firefox plugin (SearchStatus) that shows me Pagerank and Alexa information in the status bar when I visit a site. Sometimes I pay attention to these, but I always check them out for startups, as they give a useful insight into how long the sites have been active, how well they are linked, and a vague ‘doing well’ feel.
Technorati rankings seem less relevent than before, or is that just me? A new (to me) ranking that I love the concept of is SEOmoz (found via stevenmilne). The advice for this site is:
Your website/page is a relative unknown. Search engines and humans are (for the time being) infrequent visitors. Consider the accessibility of the URL, the desirability of the content and your marketing efforts online; all can have great impact on your reach.
Using data gleaned from Yahoo, Google, Wayback machine, Alexa, Technorati, del.icio.us, DMOZ and Wikipedia it constructs an overall score out of 10. This site scores 1 (unsurprisingly), techcrunch scores 7, apple.com scores 8. I’ll find a 10 eventually, I’m sure of it.
The ever present wigit to add to your page is also provided, shown here:

Note that the image isn’y dynamic, so as the score changes it will stay the same. So I could easily cheat and use the following badge:

I realise to reprocess every time an image is presented would be a huge resource drain, but to serve a saved value for 7-14 days and then reprocess would be reasonable. Or fix it to the number of requests which could also be fed into the page strength value.
Other than that small gripe Page Strength has, I think, got a reasonably good potentil to become a new standard and join PR and Alexa in my browser Status Bar as information that I just want to know. Now.