Of course! You are more than welcome to exhibit and sell your work through other means at the same time as selling them on Bluethumb, unless you have chosen to list your work exclusively with Bluehtumb under the VIP listing initiative. Please see Bluethumb VIP Listing FAQ, Terms and Conditions article for more info.
All we ask is that you ensure that your prices are the same on Bluethumb as they are on other platforms, to avoid disappointing buyers.
If you sell something elsewhere, please ensure sure to mark that work as SOLD on Bluethumb too.