19 years ago
QuantcastCollect data through ad networks and publishers. Ask sites to send data back to them.
19 years ago
CompeteToolbar-based like Alexa. Also collects data from ISPs like Hitwise and some opt-in panels like comScore. 2M in database. Deeper analysis than Alexa.
19 years ago
AlexaUsed to track ranking. Toolbar-based. Biased toward Windows/IE. Useful for comparative trends analysis. Alexa was acquired by Amazon.com in 1999.
19 years ago
comScorePanel-based methodology similar to traditional media like tv. Incentives for participants. Deep analysis. Few hundred thousand in the U.S., about 500,000 as of 2007.