Valve has introduced a $100 (£70) submission fee to its community-led indie development service Steam Greenlight.

The one-time fee is required to be paid by anyone wishing to submit a game onto Greenlight, which lets users vote for games they like the look of. Once paid, developers will be able to "post and update" as many of their own games as they like.

Valve says it introduced the fee to "cut down the noise in the system", and has "no interest in making money from [the fee]". All proceeds will go to children's charity Child's Play.

Greenlight launched last week, but has been bombarded with inappropriate and joke content.

One user submitted a sexually-explicit game called 'Titz'. Another allegedly posted a World Trade Center 'flight sim'.

Other developers, however, have been trying to make valid use of the system.

Postal 2 developer Running With Scissors is currently attempting to get its controversial game greenlit on the system.