Where to buy Contemporary Art Online?

Some suggestion from a good book 'A guide to buying and collecting Affordable Contemporary Art' by Beatrice Hodgkin, the book also go over the advantages and disadvantages of buying online:

• Artists' own website
• Platforms for graduate art like www.emergingartists.com
• Saatchi Online
• Gallery hubs such as US's 20x200, UK's Culture Label gathers works sold at a variety of UK public art galleries, commercial galleries, not for profit galleries (Matt's Gallery), Print studio (Glasgow Print Studio) and art collectives (Jaguar Shoes collective)
• Online art fairs such as VIP Art Fair, VIP stands for View in Private, have works from galleries all over the world
• Dealers such as White Cube, Gagosian, Sadie coles HQ and New York's Metro Pictures
• Online Auction Houses, such as www.backlots.com, reselling works by represented artists.
• Charity Fundraising such as the UK's homeless charity Shelter, Cancer support charity, ACRIA, UK Art Fund raises money to support public collections of art and sells works to raise funds.
• Art book publishers, many often release limited-edition prints.
• Magazine auch as ww.parkett.com, www.wallpaperselects.com, www.eyestorm.com
• Art Barter Fair, MACparis
• Royal College of Art's Secret Fair
• Art Car Boot Fair
• Buying collective
• Artist of the Month, For an annual subscription, members are sent a work of art every month for 12 months

The book also offer some tips for buying online such as asking for certificates of authenticity when purchasing editions, establishing the credibility and selection process (of art and artists) of the platform and return policy...etc.