Assuming that the entire amount is raised all the funds goes directly to the start-up, except for 7,5% which is taken by Seedrs as their commission.
If you have a great business idea, (online of offline), and just lack the cash to get it off the ground this could be an easy way for you to connect with investors.
Seedrs - Invest In Startups
They take care of all the paperwork and legal hassles connected with having a large number of investors and let you focus on launching your new business.
It's risky for the investors of course, but to me this seems like a great way to do "crowd funding". I am sure that I won't be able to stop myself from investing in some new start-ups!
Note: You can only raise money there if you have, (or is at least are willing to set-up), a UK company for the new business.