Estimating Traffic on Another Site

"Is there any way to determine the popularity, i.e., unique hits, for any given website over any given period of time?" -- John Randolph

Unique hits aren't easily obtainable except from private traffic logs. But comScore MediaMetrix (www.comscore.com) and Nielsen//NetRatings (www.nielsen-netratings.com/) publish regular data on the top sites for their clients.

Poor-man's traffic measurement is a bit cruder, but quite useful. Both Alexa (www.alexa.com) and Google (toolbar.google.com) offer toolbars that track members' web surfing habits and compile traffic rankings based on this data. The toolbars give you some indication of the amount of traffic to the website your browser is seeing. Alexa offers an average traffic rank (with Yahoo.com as #1), Google a relative page rank (with Yahoo.com as 10 of 10), though occasionally these can vary widely (see SiteSell below). Both also provide some indication of the number of hyperlinks pointing to the site. These don't seem to be terribly accurate but provide a relative measure. To give you some points of comparison I have appended monthly page view data for my own sites from recent traffic logs.

Alexa gives you the siteowner, address, phone number, and the date the domain was first put into use. You can also read Alexa user ratings and reviews and browse related links. Google Page Info includes a cached snapshot of the webpage, similar pages, and a translation into your selected language, such as to English from French, German, Italian, Spanish, and Portuguese.

I normally don't like to encumber my web browser with extras, but I use my Google toolbar several times per day. This kind of traffic and linking data can help you conduct a competitive analysis and make sense of search engine rankings that are strongly influenced by link popularity.