@OutragedFromLeeds:
Exactly right. I think any service needs to be making life better both for the sitter and for the parent - if not, there's no point!
The idea behind a commission from the sitter would be to provide the kind of checks necessary to allow them to get more bookings, which would be explained clearly. They would have to be getting more money, otherwise there would be no incentive for them to use it.
In terms of 'why would they stay?', if the majority of the babysitting work was 'ad-hoc', then there's the potential to get more work through using an agency like this, and hence to make more money.
The sitter going into a stranger's house is an interesting point. You can do a lot of good by forcing parents to log-in with a social network, which should help build up trust on the sitter side, I imagine. I need to check with more sitters about their thoughts on this, but it looks like currently agencies don't vet the parents, right?
In terms of the payments, you bring up an interesting point - I believe this is usually set by the agency, but it's important to be fair to both parties (cancellation policies, extensions to the time etc).
The point of 'being chosen' is another interesting one. I understand that from a parent's point of view, you want that sitter to be confirmed as soon as you make the booking, but from the sitter's point of view, you want to have the choice. Tricky one. What do you think about giving a sitter a (let's say) 10 / 30 / 60 minute window to accept the job? How does that sound from a parent's point of view?
Just above here on this thread lotsofcheese said that they didn't use Sitters (as a parent) because it was too expensive, but your experience is that Sitters find that they are underpaid. Sounds like someone is taking a far bigger cut than they should be...I'm a firm believer that both parties should be happy, but it sounds here like the only happy party is the middleman!