Is an RSVP of 3 weeks to short?

It shouldn't be! If you have already sent out STD then most guests should know if they are going or not and it only takes a day or two to get organised to send a response.

Could you give options for responding including email or a facebook page making RSVPs as expedient as possible?

I wouldn't say so, in fact sometimes having an RSVP date too far in advance is worse as people might think they have ages then just forget or not get round to it. If they know they haven't got long then then they might be a bit more organised.

Just because I'm nosey and trying to organise the rest of my stationary, can you say who you ordered yours with?

Hiya;

I wish we had only given 3 weeks! People just leave you hanging otherwise. We gave 2 months and I have been chasing people this week who knew they were coming/not coming as soon as they received the invite.

I think if you give too long people put it to one side and forget about it.

We sent ours out with just over 3 weeks' deadline. Only had to chase up one person out of 82 invitees. About half of the people sent back the cards, the rest e-mailed (we set up a special wedding e-mail for the purpose but you could use your own).