Perhaps I should have separated them, then (assuming other people think like you do). I guess I consider them the same because people are similarly taking the initiative to share the link on-line with a community, be it their friends or a more general community.
It's not the general intent ("sharing") or the community that differentiates them to me. It's the action. Adding a bookmark to del.icio.us is quite different to saying "Wow! Check out this awesome site http://example.com/" on Twitter to my followers - not at a technical level, for sure, but in terms of potential effect.
