First, it’s important to understand that the four platforms you list fall into two very distinct groups.
Kickstarter and IndieGoGo are project-based crowdfunding platforms through which anyone can contribute money, either as a donation or with the promise that they will receive a tangible ‘reward’ of some kind if the project is successful.
Gust and AngelList are equity-based platforms, used by Accredited Investors to facilitate the investment of money for an ownership interest in a company.
As such, depending on what you are trying to do (fund a project or get permanent investors into your company), you would select one group or the other.
Once you’ve done that, for the first group it doesn’t make sense to participate on more than one platform. That’s because in the vast majority of cases, most of your contributions will be coming from your own network, and you don’t want to divide them up (since you will need to hit your ‘target’ minimum raise.)
For the equity group, however, it is not uncommon (and there is no downside) to listing on both Gust and AngelList. Neither has any cost to establish a profile, and both provide visibility to active angel investors and others in the startup ecosystem (Gust primarily to organized investors and funds, AngelList primarily to independent investors).
*original post can be found on Quora @ http://www.quora.com/David-S-Rose/answers *