Number of sites using Microdata and other formats are growing day by day. End of 2013 there has been 1,779,935 domains detected with 4,264,562,758 entities (mixed formats). To be specific, there are 463,539 domains, 276,348,609 URLs, with 1,964,777,851 entities using Microdata format. So here is a list of a few that this library can be tested with. Please add any further sites to the top.

• doulas.club A brazilian catalog of doulas, uses microdata on its home page and on each of the profile pages (here's an example).
• [Ephesus Breeze Tours] (http://ephesusbreeze.com) A Turkish tour operator, using microdata for marking up : TravelAgent, TravelAction, TouristAttraction, Places, Person on reviews, Prices etc. TravelAction example on [Ephesus Tours from Kusadasi] (http://ephesusbreeze.com/ephesus/tours/kusadasi-ephesus-fullday) page.
• [Matériel Grand Format] (https://www.materiel-grand-format.fr) The first French plotter reseller in Europe , uses microdata for marking up products, prices, customer feedback and reviews. Example for product: HP Designjet T940. Example for review: Canon PF-03.
• [European Hair Transplant] (http://europeanhairtransplant.se) A swedish/Polish clinic, uses microdata for marking up persons, places, prices etc
• [The Holiday Place] (http://holidayplace.co.uk/about/customer-feedback) An independent tour operator in the United Kingdom, specialist crafting tailor made holidays and multi-centre escapes, uses microdata to display customer feedback and hotel reviews.
• Southern Africa Travel An African travel agency and tour operator, using microdata to match their location hierarchy and url schema to data entities - African tourist attractions contained within regions, contained within countries, contained within Africa (continent) with tours (products) matched to the destinations. There's more - linked author and publisher accounts for all content, blog posts are articles, local businesses (the TravelAgency itself, and many accommodations - using LodgingBusiness), popular travel brands, reviews - the list is growing. Example: Cape Town region template in the structured data testing tool and the Cape Town page itself.
• Ebizindia An Internet marketing company uses author markup to get owner's Google profile photo displaying in the results. Example: Search for Ebizindia on Google
• CTS Wholesale Sunglasses An online wholesale sunglasses store using microdata for customer reviews. Example: Wholesale Sunglass Reviews
• Voyagepedia A French travel encyclopedia using mainly Microdata for tourist attractions and guides. Example: Guide to Seychelles
• US Insurance Net Microdata mainly used for insurance company reviews. Example: Progressive Insurance Reviews.
• The Telegraph A British Newspaper marking up its restaurant reviews. Example: Bunga Bunga, London, restaurant review. Is marked up slightly incorrectly, where they have put the address and contact details in the reviewBody, instead of separating it out and marking that up separately.
• Durch Schmutzige Strassen Blog maintained by Mathias Roth. Uses lots of general page mark-up such as: http://schema.org/WebPage, http://schema.org/WPHeader, etc. As well as more specific mark-up such as http://schema.org/Book, http://schema.org/BlogPosting. Example: [Das Buch ist tot, es lebe das Buch](http://strassen-030.de/es-lebe-das-buch /)
• Media Decay Microdata is used to describe Music, Films, TV and Books. Example: Punching the Clown Movie Review
• Indianapolis Museum of Art Microdata is used to describe items in the collection. Example: Roman Capriccio: The Pantheon and Other Monuments. Note that the example does miss out the name of the work in the Microdata.
• Steve: The Museum Social Tagging Project A place where you can help museums describe their collections. Example: Soap Bubbles
• Trust a Friend A review site using Microdata to describe the items reviewed. Example: The Dog (Toby Carvery), Over, Gloucestershire
• Mida Project Page Uses microdata to describe the copyright holder on the license and to describe the news.
• Techtinkering Uses Microdata to markup book reviews. Example: Book Review: Electronic Brains: Stories from the Dawn of the Computer Age by Mike Hally
• NCSU Libraries' Digital Collections: Rare and Unique Materials Uses Microdata. Example: Drawing of Grove Arcade
• Norgeskatalogen Uses microdata and RDFa to mark up companies, reviews and aggregated reviews. Example: Company listing
• Qomun: Uses microdata to mark up free and libre creative works and organizations. Example: Cat Toy, Move Commons
• Best Buy: Large US electronics retailer. Example