thanks for advices. regarding twitter - no, never, no tweets. by the way, this is something someone could communicate to twitter - they actually say what permissions you give us (read your timeline + know whom you follow = to tell if your friends are here)
there's a little problem - we have autosave. so, there's not a single button after you make a new chart where we could ask to login. I strongly agree that it is aggressive that we ask to authorize this way. what's better:
a) descriptive images / screenshots on front page (aka "learn more")
b) add a save button (then ask for login), unless it's pressed no data is saved.
thanks, I start to agree with you:) Do you think screenshots alone would help or software should be usable without authentication till some period (like when you need to save something?)
There's way too much elements on front page. Idea is good, yet not unique, I'd suggest focusing on design, first by removing 90% of content that doesn't essentially matter.