I see a lot of webcomics on social networks like facebook and tumblr and I was wondering if you (as an author) weren't afraid of losing the rights you have on your creation. It seems to me that, in a way, the terms of service of those websites could easily lead to abuses.
Subscriber Content License to Tumblr:
When you transfer Subscriber Content to Tumblr through the Services, you give Tumblr a non-exclusive, worldwide, royalty-free, sublicensable, transferable right and license to use, host, store, cache, reproduce, publish, display (publicly or otherwise), perform (publicly or otherwise), distribute, transmit, modify, adapt (including, without limitation, in order to conform it to the requirements of any networks, devices, services, or media through which the Services are available), and create derivative works of (including, without limitation, by Reblogging, as defined below), such Subscriber Content. The rights you grant in this license are for the limited purpose of operating the Services in accordance with their functionality, improving the Services, and allowing Tumblr to develop new Services. The reference in this license to "derivative works" is not intended to give Tumblr itself a right to make substantive editorial changes or derivations, but does enable Tumblr Subscribers to redistribute Subscriber Content from one Tumblr blog to another in a manner that allows Subscribers to, e.g., add their own text or other Content before or after your Subscriber Content ("Reblogging").
For content that is covered by intellectual property rights, like photos and videos (IP content), you specifically give us the following permission, subject to your privacy and application settings: you grant us a non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use any IP content that you post on or in connection with Facebook (IP License). This IP License ends when you delete your IP content or your account unless your content has been shared with others, and they have not deleted it.
I understand perfectly that those terms exist (in part) to allow a good functionnement of the website but is it really secure ?
So, what do you think about it ?