Do you mean the daily support goal on the news page? If you click on it and see, it's actually the daily site-wide goal for support, not personal user goals :) Whilst Subeta is free to play, there are additional options to buy special items /perks via gold account, etc. via cash shop credits. You don't have to if you don't want to, it's just a means of supporting the site and getting some nice perks or items out of it. The items/credits can be sold for sP too, if you like :)

If the sitewide support goal is achieved often (or consecutively for a period of time), sometimes to show appreciation, Subeta will release a perk or something via the news to say thanks to everyone :)

Hope that's clear!