Hatena's online services and Twitter can be linked by using the OAuth* authentication protocol
You can set this up easily to post the entries and image uploads you make on Hatena to Twitter, and also to post your tweets on Twitter to Hatena.
Hatena Monolith allows you to scan barcodes from any kind of product that exists around you. You can use Monolith to easily keep track of your collections or to introduce things you like with others, and enjoy sharing your purchases and collections in a whole new way.
You can simultaneously post to Twitter
The OAuth authentication protocol allows you to connect to external services without sharing private information such as your password, and enables linking between the various functions on these services. Hatena uses OAuth to link functions with Twitter, and your Twitter password is never disclosed to Hatena, so you can use these services together safely.