Massive difference!
I am a bit of a technophobe. Admittedly, more publicity brings in more animals and more than get rehomed but last week we put out an appeal on Facebook and website regarding Dartmoor ponies within 1 hour we found a home for the 2 remaining fillies and have raised enough money for transportation.
Local journalists also read our website and will put things in the paper based on stories on our website without letting us know (which is fine as it is there for public viewing).
I can't tell you how important it is to keep it upto date tho as people get frustrated if things aren't upto date. We have groupies and fans that read our website all the time as we treat it like a bit of a blog and put regular news on it.
Also, if someone rings up and I haven't really got time to speak then I point them to the website as we have a lot of info on there.
Sadly, our website makes us look like a big organisation and we get people writing to ask for jobs (clearly people who haven't actually looked at the website properly and seen how we run) and then they get grumpy when we don't have time to reply.:?
If you can get volunteers to set up a website or do Facebook for free then that makes a massive difference too. The cost of making a website is massive and one of our volunteers set up ours and made it user friendly so that we can update it and it doesn't cost anything. We do ours in 'Wordpress' and it means that I can update it.