it depends on what you want to to analyze, logs are best, if you can't get logs then alexa is one tool, if you're aware it can be easily manipulated now
check links and quality of links to
check mentions in usenet
check link pages as to what that site is linking to it for
it really depends on why you're looking at the name, if you look at sites as how many people go now and how many pennies can I make then you need to look at most of the stuff above to see if the traffic is real, if someone is selling it to you direct due to traffic then grab the logs
if the name is for development does it contain the root name of that type of topic
alexa is just a quick check if you ask me to see if a site is getting decent traffic, it does not mean it is anymore when a site has a strong alexa
it's a good sign that the site might be 1000 or more uniques a day if it is top 100K that is all that 100K at Alexa means
I have many sites with that many uniques for many years and most were top 100K at alexa or at least top 200K
A few of the busier sites have 5K uniques most days that I run and they never get high on Alexa, so it's not a perfect tool and it has never been such a tool
Also, beware of sites with high page views per user, that really skews alexa
there are so many reasons why people look at owning a domain name that your answer can't be shoe boxed into one simple answer