Bluethumb acts as your agent in relation to the sale of art and collects proceeds on behalf of the artist before deducting commission and shipping costs. The remaining funds are paid to the artist (Artist Margin), more details can be found in the terms and conditions.
Depending on your profile settings, listed prices may include GST, and as such, you (and not Bluethumb) are liable to remit such GST (if any) on the taxable supply of the art in accordance with the 'A New Tax System' (Goods and Services Tax) Act 1999.
It is the responsibility of all artists on Bluethumb to make sure they are handling their personal taxes correctly. If an ABN is not provided and an appropriate exemption for not having an ABN is not provided, the ATO requires that Bluethumb withold tax at a rate of 47%. We recommend that you seek professional advice on whether you should or should not register for GST or an ABN, and update your profile accordingly.