added one additional service and changed formatting to make a clearer difference between the reputation-sites and obviously only/mainly malware-scanning...
URLVoid looks like a "meta-engine"; it scores sites based on a bunch of other services. it provides links to all individual results and displays some additional information like ip-address, location, hoster, etc.
- it is just a web-service, so no software is available but they provide a experimental API to query URLVoid database.
- the ratings are done by the individual services and it seems that they are mainly companies (maybe some of them with community-contribution and/or transparent scoring or even not).
although about itself there is very few information and just is spanish, it looks interesting and nice polished to me. it works up some different information from sources like WOT, MozRank, Alexa and displays them beside whois- & certificate-information.
- as far as is see it is only a website.
- the rating comes obviously at least partly from MyWOT, but they also give the ability to send your own reviews with thumb up/down and a comment.
Norton Safe Web
it looks like Norton Safe Web only scans for viruses but no really further information is given.
- a dedicated software just for ratings is not available, it is just a website.
- there is no information how the scoring is done, but additionally a community rating with the number of users who rated is displayed.
McAfee SiteAdvisor checks for various dangers like downloads, links, phishing, spam, etc.
- beside the website it seams that there is also at least a windows-software.
- the scoring is entirely done by the company.